> I certainly will not publish any of my software open source, despite how much I would like to (under GPL) in order to help fellow developers.

I think this is a rather radical approach. You're undermining the OSS movement because you dislike Microsoft (I do too). I think adding a clause or dual licensing your work is more effective at stopping big-tech funded AI crawlers than just not adhering to open source.

You can host your code on sourcehut or Codeberg (Forgejo), you don't NEED to host it on a Microsoft owned platform.