Use the Monaspace Var variant, only it is properly found at the minute.

Until githubnext/monaspace#111 is fixed/its PRs are merged.

.config/kitty/kitty.conf

@@ -5,11 +5,10 @@
 #: kitty has very powerful font management. You can configure
 #: individual font faces and even specify special fonts for particular
 #: characters.
-
-font_family      Monaspace Argon Regular
-bold_font        Monaspace Argon Bold
-italic_font      Monaspace Argon Italic
-bold_italic_font Monaspace Argon Bold Italic
+font_family      family="Monaspace Neon Var"
+bold_font        auto
+italic_font      auto
+bold_italic_font auto
 
 #: You can specify different fonts for the bold/italic/bold-italic
 #: variants. To get a full list of supported fonts use the `kitty