Good afternoon; I ran into a similar problem about a month ago and could help you if your question is still relevant. I would like someone to answer me like that and offer their help, but unfortunately, there was no such thing, and I solved this problem on my own. It turned out that I needed to thoroughly clean my computer for it to start working normally again without constant shutdowns, although I was also thinking of buying a new one. An article about the release of
the space for mac helped me. So please do not rush to throw away your old computer; perhaps it will still be able to serve you for some amount of time.