Hello The Hammer,
If macOS High Sierra is working well with your computer, it's OK to stay on that OS for awhile. Currently, I have macOS Mojave running on my 2013 Mac Pro. In my experience, it's been a rock-solid OS on my machine and I don't intend to upgrade the OS in the foreseeable future.
As for macOS Catalina, that's a different story. I have macOS Catalina on two of my other experimental, non-critical computers. While everything works "OK", there are Bluetooth problems and general "instability".
Regarding macOS Big Sur, it will be a long while before I start experimenting with that!
richmlow