If you weren’t aware, Nextcloud provides non-AIO compose files in their docker repo: https://github.com/nextcloud/docker/blob/master/.examples/docker-compose/with-nginx-proxy/postgres/fpm/docker-compose.yml

NVMe drives aren’t guaranteed to be fast. Based on those stats I’m guessing you have QLC and no DRAM.

Sliger has a few rackmount chassis which are only 15 inches deep.

0.04 seems reasonable. Does the problem go away if you set it to 0?

What method did you use to determine the pressure advance value and what value did you select? If the number is too large you will get very odd behavior.