That's exactly the symptoms that I saw with my Rpi 4b. The desktop slowed down more and more, taking longer and longer to respond. Then the out of memory error..
After I implemented an earlier suggestion to turn off all notification sounds, it seemed to stop slowing down.
I currently have the simulator running doing several hours of tracking and capturing. The system is currently losing about 250MB of free memory every hour. That's not enough to explain what I see, which is memory running out after about 3-4 hours of tracking and capturing. I do have notification sounds turned off though, so I'll redo with them on so see if there is a difference.

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