NC resource (memory) demands in LNMP server

Hi,
I have setup a LNMP (Alpine Linux, Nginx, MariaDB, PHP) in LXC.
Due to restricted resources on the host the memory allocation for this container is very small, means 200MB memory, 20MB swap.
Monitoring the LXC resources shows that (in hourly avg.) 60% of available memory is allocated.
However swap memory is 100% utilized.

Question:
Can you share some information what is constantly / temporarily allocating memory running NC?

THX

There are in general the cronjobs that create some load. Except for that, there needs to be user (or client) interaction. But that is only Nextcloud, nginx, database, … need some permanent resources.