Cannot access wp-admin – redirect issue

When I try to access the wp-admin or wp-login.php of my site. I either get a 404 or a 500 error. Everything on the front-end appears to work just fine though.

During live chat, we tried disabling all plugins by moving them out of wp-content/plugins, and disabled all cache as well by renaming cache files & commenting out defines in wp-config.php. No luck.

We also refreshed security keys in wp-config.php and enabled both WP_DEBUG & WP_DEBUG_LOG, but no joy there either; there wasn’t even the expected debug.log file to find any clues.

Can you please help me get back into my admin? Thanks!