OH4 Basic UI very slow


so after upgrading to OH4 I migrated my sitemap from the file based configuration to the UI configuration and created a page where I just copied the whole sitemap into.
I don’t know if this is the reason, but when I restart OH4, it takes ages to load the basic UI in the Android app for the first time, I usually get timeouts and have to reload. I have a lot of sub-pages and with everyone of them I face the same issue - loading for the first time, timeout, wait for some seconds, reload.

This has not been the case in OH3 and before, I was used to restart my server each day because of OutOfMemories or other issues. The good thing is that since OH4 I didn’t face such issues anymore, the bad thing is that I’m always afraid of restarting my server…

Runtime Environment: Openhabian on Raspi4 4GB