When I installed the preview, I'm sure I read that the normal update route doesn't work (that is no auto updating nor clicking the update button). If this is the case, how do I check that the preview download offered from the preview site is a newer version than the one I have?
I am not sure about whether updating works or not, but you can just check the build number in the app menu Parallels Desktop > About Parallels Desktop Then compare it to the build on the Technical Preview page - "Parallels Desktop 16 for M1 Mac build 50393"