Strange internet glitches on MacBook, what to do?

Question

macOS

I have a macbook that has been running macOS High Sierra for a long time. But then I decided to upgrade to a newer version, macOS Catalina. In general, ten times I regretted that I had updated. A strange glitch happened about a month ago. The system completely hung, did not react to anything, the cursor was at first a colored ball, and then disappeared altogether. I was able to “revive” the macbook by closing the lid, opening it (when opening it was in the off state, that is, the black screen and that’s it), waiting for 20 seconds and holding the power button, after which the apple appeared, and the computer booted up and started working as usual . But after that, problems with the Internet began. Firstly, some sites do not open in Chrome, although everything works fine in Safari. Secondly, files stopped uploading to some sites. Files are downloaded from the Internet as usual, but to upload a file somewhere, You need to transfer it to the phone and load it from the phone. Rebooting the macbook didn't help. And just yesterday, the above-described glitch with a hangup repeated. After that, the Internet “flew off” even more, some sites on which everything worked fine also stopped accepting my files (they write that an error occurred or something like that). I've already checked my computer for viruses, the antivirus found nothing. So here are my questions:
1. What could be causing this strange computer freeze?
2. What are the possible ways to solve the problem?
3. Version of my macbook: macOS Catalina 10.15.5. There are already the sixth and seventh "Catalina" with bug fixes. I’m thinking of installing it (what if not only I have this bug, Apple is aware of it and has already fixed it?), But it’s somehow scary, suddenly something hangs along the way. So, is it worth upgrading?
I would be grateful to those who will tell you possible ways to solve the problem.