diff --git a/packages/style-engine/class-wp-style-engine-css-declarations.php b/packages/style-engine/class-wp-style-engine-css-declarations.php
index 092b4e204647b..13ec0d5142bf5 100644
--- a/packages/style-engine/class-wp-style-engine-css-declarations.php
+++ b/packages/style-engine/class-wp-style-engine-css-declarations.php
@@ -40,22 +40,6 @@ public function __construct( $declarations = array() ) {
 		$this->add_declarations( $declarations );
 	}
 
-	/**
-	 * Checks a CSS property string to see whether it is a valid CSS custom property.
-	 * In conjuction with static:sanitize_property it only allows `--wp--${slug}--{$kebab_case_css_property}`.
-	 *
-	 * This explicit checks is required because
-	 * safecss_filter_attr_allow_css filter in safecss_filter_attr (kses.php)
-	 * does not let through CSS custom variables.
-	 *
-	 * @param string $css_property The CSS property.
-	 *
-	 * @return boolean
-	 */
-	protected function is_valid_custom_property( $css_property ) {
-		return 1 === preg_match( '/^--wp--[a-z]+--[a-z0-9-]+$/', $css_property );
-	}
-
 	/**
 	 * Add a single declaration.
 	 *
@@ -115,11 +99,7 @@ public function get_declarations_string() {
 		$declarations_output = '';
 
 		foreach ( $declarations_array as $property => $value ) {
-			$declaration = "{$property}: {$value}";
-			if ( ! static::is_valid_custom_property( $property ) ) {
-				$declaration = safecss_filter_attr( $declaration );
-			}
-			$filtered_declaration = esc_html( $declaration );
+			$filtered_declaration = esc_html( safecss_filter_attr( "{$property}: {$value}" ) );
 			if ( $filtered_declaration ) {
 				$declarations_output .= $filtered_declaration . '; ';
 			}
diff --git a/packages/style-engine/class-wp-style-engine.php b/packages/style-engine/class-wp-style-engine.php
index 70bde74efe34f..9524fff044b35 100644
--- a/packages/style-engine/class-wp-style-engine.php
+++ b/packages/style-engine/class-wp-style-engine.php
@@ -142,7 +142,7 @@ class WP_Style_Engine {
 			),
 		),
 		'spacing'    => array(
-			'padding'  => array(
+			'padding' => array(
 				'property_keys' => array(
 					'default'    => 'padding',
 					'individual' => 'padding-%s',
@@ -152,17 +152,7 @@ class WP_Style_Engine {
 					'spacing' => '--wp--preset--spacing--$slug',
 				),
 			),
-			'blockGap' => array(
-				'property_keys' => array(
-					// @TODO 'grid-gap' has been deprecated in favor of 'gap'.
-					// See: https://developer.mozilla.org/en-US/docs/Web/CSS/gap.
-					// Update the white list in safecss_filter_attr (kses.php).
-					// See: https://core.trac.wordpress.org/ticket/56122
-					'default' => 'grid-gap',
-				),
-				'path'          => array( 'spacing', 'blockGap' ),
-			),
-			'margin'   => array(
+			'margin'  => array(
 				'property_keys' => array(
 					'default'    => 'margin',
 					'individual' => 'margin-%s',
@@ -374,7 +364,6 @@ protected static function get_css_declarations( $style_value, $style_definition,
 		$css_declarations     = array();
 		$style_property_keys  = $style_definition['property_keys'];
 		$should_skip_css_vars = isset( $options['convert_vars_to_classnames'] ) && true === $options['convert_vars_to_classnames'];
-		$custom_css_property  = isset( $options['custom_properties'] ) && is_array( $options['custom_properties'] ) ? _wp_array_get( $options['custom_properties'], $style_definition['path'], null ) : null;
 
 		// Build CSS var values from var:? values, e.g, `var(--wp--css--rule-slug )`
 		// Check if the value is a CSS preset and there's a corresponding css_var pattern in the style definition.
@@ -382,8 +371,7 @@ protected static function get_css_declarations( $style_value, $style_definition,
 			if ( ! $should_skip_css_vars && ! empty( $style_definition['css_vars'] ) ) {
 				$css_var = static::get_css_var_value( $style_value, $style_definition['css_vars'] );
 				if ( $css_var ) {
-					$css_property                      = $custom_css_property ? $custom_css_property : $style_property_keys['default'];
-					$css_declarations[ $css_property ] = $css_var;
+					$css_declarations[ $style_property_keys['default'] ] = $css_var;
 				}
 			}
 			return $css_declarations;
@@ -397,8 +385,7 @@ protected static function get_css_declarations( $style_value, $style_definition,
 				if ( is_string( $value ) && strpos( $value, 'var:' ) !== false && ! $should_skip_css_vars && ! empty( $style_definition['css_vars'] ) ) {
 					$value = static::get_css_var_value( $value, $style_definition['css_vars'] );
 				}
-				$css_property        = $custom_css_property ? $custom_css_property : $style_property_keys['individual'];
-				$individual_property = sprintf( $css_property, _wp_to_kebab_case( $key ) );
+				$individual_property = sprintf( $style_property_keys['individual'], _wp_to_kebab_case( $key ) );
 
 				// If the style value contains a reference to another value in the tree.
 				if ( isset( $value['ref'] ) ) {
@@ -410,8 +397,7 @@ protected static function get_css_declarations( $style_value, $style_definition,
 				}
 			}
 		} else {
-			$css_property                      = $custom_css_property ? $custom_css_property : $style_property_keys['default'];
-			$css_declarations[ $css_property ] = $style_value;
+			$css_declarations[ $style_property_keys['default'] ] = $style_value;
 		}
 
 		return $css_declarations;
@@ -508,10 +494,7 @@ public function generate_global_styles( $global_styles, $options ) {
 
 		// Layer 0: Root.
 		$root_level_options_defaults = array(
-			'selector'          => 'body',
-			'custom_properties' => array(
-				'spacing' => array( 'blockGap' => '--wp--style--block-gap' ),
-			),
+			'selector' => 'body',
 		);
 		$root_level_options          = wp_parse_args( $options, $root_level_options_defaults );
 		$root_level_styles           = $this->get_block_supports_styles(
diff --git a/packages/style-engine/phpunit/class-wp-style-engine-test.php b/packages/style-engine/phpunit/class-wp-style-engine-test.php
index 25ccf7561813c..2cbe2ef62d449 100644
--- a/packages/style-engine/phpunit/class-wp-style-engine-test.php
+++ b/packages/style-engine/phpunit/class-wp-style-engine-test.php
@@ -488,8 +488,7 @@ public function data_generate_global_styles_fixtures() {
 						'background' => 'var(--wp--preset--color--background)',
 					),
 					'spacing'    => array(
-						'blockGap' => '2rem',
-						'padding'  => array(
+						'padding' => array(
 							'top'    => '10%',
 							'right'  => '20%',
 							'bottom' => '10%',
@@ -503,7 +502,7 @@ public function data_generate_global_styles_fixtures() {
 					),
 				),
 				'options'         => null,
-				'expected_output' => 'body { color: var(--wp--preset--color--foreground); background-color: var(--wp--preset--color--background); padding-top: 10%; padding-right: 20%; padding-bottom: 10%; padding-left: 20%; --wp--style--block-gap: 2rem; font-size: 1rem; font-family: var(--wp--preset--font-family--system-font); line-height: 2; }',
+				'expected_output' => 'body { color: var(--wp--preset--color--foreground); background-color: var(--wp--preset--color--background); padding-top: 10%; padding-right: 20%; padding-bottom: 10%; padding-left: 20%; font-size: 1rem; font-family: var(--wp--preset--font-family--system-font); line-height: 2; }',
 			),
 			'compiles_with_ref_pointers'               => array(
 				'global_styles'   => array(
@@ -512,11 +511,11 @@ public function data_generate_global_styles_fixtures() {
 						'text'       => array( 'ref' => 'styles.color.background' ),
 					),
 					'spacing' => array(
-						'blockGap' => '2rem',
-						'padding'  => array(
-							'top'    => array( 'ref' => 'styles.spacing.blockGap' ),
+						'margin'  => '2rem',
+						'padding' => array(
+							'top'    => array( 'ref' => 'styles.spacing.margin' ),
 							'right'  => '20%',
-							'bottom' => array( 'ref' => 'styles.spacing.blockGap' ),
+							'bottom' => array( 'ref' => 'styles.spacing.margin' ),
 							'left'   => '20%',
 						),
 					),
@@ -528,7 +527,7 @@ public function data_generate_global_styles_fixtures() {
 					),
 				),
 				'options'         => null,
-				'expected_output' => 'body { color: #ffffff; background-color: #ffffff; border-top-width: 20%; border-top-style: dashed; padding-top: 2rem; padding-right: 20%; padding-bottom: 2rem; padding-left: 20%; --wp--style--block-gap: 2rem; }',
+				'expected_output' => 'body { color: #ffffff; background-color: #ffffff; border-top-width: 20%; border-top-style: dashed; padding-top: 2rem; padding-right: 20%; padding-bottom: 2rem; padding-left: 20%; margin: 2rem; }',
 			),
 			'ignores_other_top_level_keys'             => array(
 				'global_styles'   => array(