bug: How to capture the upstream error for all the status codes greater than 300

[btalakola]

Current Behavior

Hi Team, First of all a very big thank to big chunk of work done on apisix side.
I have requirement to capture the upstream error which should not be intercepted by nginx. Currently APISIX relies on NGINX to handle errors at the gateway layer, so when an error like 404 or 500 occurs, NGINX will return a simple default error page with the relevant HTTP status. These default pages are standard HTML pages that NGINX automatically returns when an error is detected. Instead of showing standard HTML pages intercepted by nginx, can we capture the upstream error and show it in UI?
Regarding the other alternative response-rewrite which again show custom error messages not the upstream errors.

Expected Behavior

Need to capture the upstream error messages for the status > 300

Error Logs

No response

Steps to Reproduce

I have requirement to capture the upstream error which should not be intercepted by nginx. Currently APISIX relies on NGINX to handle errors at the gateway layer, so when an error like 404 or 500 occurs, NGINX will return a simple default error page with the relevant HTTP status. These default pages are standard HTML pages that NGINX automatically returns when an error is detected. Instead of showing standard HTML pages intercepted by nginx, can we capture the upstream error and show it in UI?
Regarding the other alternative response-rewrite which again show custom error messages not the upstream errors.

Environment

APISIX version (run apisix version):
Operating system (run uname -a):
OpenResty / Nginx version (run openresty -V or nginx -V):
etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info):
APISIX Dashboard version, if relevant: