Wait...am I missing something here? My iStat still has nothing for sensors section at all. I finally gave up on them updating it for my 14" MBP and just launch this nifty MX Power Gadget when I want to see info.iStat was updated with M1 support almost immediately. No idea why you claim it wasn't.
Edit: Ah you are talking about the App Store version. This one has always been kind of unusable but that's Apple's fault.
Does your iStat show sensors on the new Macbook Pros?
EDIT: I WAS missing something! Version 6.60 was showing nothing, but I found 6.61 on their website and installed that; now I have sensors! But I wonder why the apps build in "check for updates" never saw or updated to this new version. Crazy.