[MAYBE SOLVED] HTTPS site losing PHP connection overnight!

I may be wrong, but it seems to me that you have a problem on the path from the browser to the server. But not including the framework.
Set environment as development in the .env file.
See server logs.

The server was still going down overnight but at least errors were reported thanks to strict_types=1;

After well over a week I bit the bullet and purged apache2 and a2dismod php7.4... then reinstalled apache2 and php8.0. It took a while but eventually after installing a2enmod missing apache2 modules and using certbot to reinstall about sixteen domains the new domain was still going down overnight!!!!!

Fortunately I had a spare domain (which is seldom used) and swapped all the content from the new domain to the spare domain and the new domain has not gone down!!!