Swap Skyrockets out of the blue & System becomes unresponsive, Persistence stops

I am looking for some hints on my OH4-Problem described in the Title. Recently Updated to OH4.0.1. I am unable to have Openhab running stable since then. Whenever I restart OH, things are doing well - then after a random amount of time the System becomes unresponsive, the persistence stops working. I had no luck with various approaches based on the forum:

  • Removed last “old” DSL-Rules
  • Removed the refreshing Image Items
  • Deleted bindings i hat in suspect
  • tried with xms & xmx-Settings

Here is an example from tonight - at around 02:00; when nothing special was happening, SWAP startet Skyrocketing out of the blue and Persistence stopped around 04.00. Nothing unusual to see in the log’s.

I had “some” issues with the previous version (OH 3.4) on persistence stopping stopping for a few hours in some nights, but i didn’s track that down. Do you have some approaches for me in mind?
Many Thanks in advance!

OpenHab is running as Docker Container on SynologyDiskstation 918+ with 8g of Ram, the Docker Container has high priority and shows no unusual load (CPU 1.4% and Memory 1.4g - as example from this moment). 120 Things, 731 Items, 196 Rules. Installed Bindings: Astro, KNX, Nuki, Systeminfo, deCONZ, MQTT, Openweathermap, Unifi, HTTP, myStrom, Shelly, IPCamera, Network, Sonos, Metrics, ohCloud. Persistence is RRD4J standard, nothing changed.