Occasional freezes and high RAM and SWAP consumption

I had Zorin 15.3 installed and it was excellent for Zoom dance classes during Covid lockdown. Also the multiple desktops and ability to move program windows horizontally to other desktops and having small overviews of each in the taskbar.
All this I miss in Zorin16 and the vertical arrangement of desktops is got less functionality.
But really irritating is the random freezes of the system. I found by observing the taskmanager that RAM and SWAP are nearly fully used. While writing this, RAM usage is about 70% and SWAP 100% (2.4 of 3.5GB and 1/1GB SWAP), with two terminal windows open, a file manager and a Mozilla with only three tabs.
Also irritating is the fact, that the connection to the WLAN is often forgotten.
Is there any experiences out on how to reduce RAM and SWAP consumption, e.g. with turning-off unnecessary functions like jelly mode etc.?
It is a not so old Lenovo laptop T430 w/ 4GB RAM and SSD and I got just the right adapter to connect it to my Bravia TV as secondary monitor (not yet tried with Z16, surprises expected).

This sounds a lot like a memory leak. Can you run a memory test; check Gnome-software...

Thanks for this suggestion! Do you think some components of the UI have this memory leak? And if I've found them, what to do with this information??
I wanted to e.g. increase the swap because I've got plenty of SSD space. This is not removing the root cause - I know - but to keep me continue to test Zorin 16...
Today I found that the card reader is not working :frowning:

I think it is possible and it could cause the high memory usage. The usual fix for it is to reinstall the software that is causing the memory leak.