Catalina: After some hours various things start to crash and/or stop working

I would pick one app and troubleshoot it.

1. Remove chrome extensions (make a list so you can reinstall them later)
2. Remove Chrome
3. Reinstall Chrome
4. If it still crashes - remove it and make a new admin account (clean environment)
5. Reinstall Chrome when the main user is logged out and only the new user is logged in.
6. Pursue support with that one vendor to isolate further if the app is supported on your version of Catalina.

Apply any Apple patches that are released while you are isolating things above.

I had the same problem and now I think it's completely gone.
It turned out, after updating to Catalina, that old cron jobs start a single process everytime they should run.
I had a (forgotten) job running every minute and after a while I found hundreds of cron processes in Activity monitor, so I killed all of them and finally retake control on my computer.
Eventually the solution was to comment/delete the lines in the crontab of the user root and magically everything started to work again as expecting.

Reference https://discussions.apple.com/thread/250789736