I was working on upgrading a PHP 5.6 app to 8.3 and ran into this. For me the answer was that my database errors from PDO were disabled and one of my queries was failing for an incorrect integer values. In earlier versions of MySQL (v5) this wasn't an error but in the latest (v8) is is.

What was happening is that I got the white screen but no errors in the apache error logs and nothing displayed to the screen. The DB error from the query triggered a silent fatal error that didn't get logged anywhere.

Once I enabled the PDO errors again I was able to debug the issue.