Admin session expiry not working despite being set in admin and php settings

Admin session expiry is not working in Magento 2 (2.3.5-p1).

We have it set in the backend admin configuration:

We also have it set in the php session.gc_maxlifetime:

Still though, session expiry in backend is less than an hour (I am not sure how long exactly).

I am unsure what else I can try…

Session files were being saved to /var/lib/php/session on the server although we have just defined a path within Magento environment at var/session to see if this makes a difference.

The website is running PHP as FPM application served by nginx (if that helps or makes a difference).