Avid Pro Audio Community - Weird problem with heat

Hey all!
I have a very weird problem with my new Macbook Pro 16 inch:
First, I bought a refurbished Macbook Pro 16 inch, i9, 2,4 ghz 8 cores, 32 gb ram, 1 tb ssd. I installed it by using a time machine backup from a hard drive that I use for these backups. Everything worked fine. But then: When I open Pro Tools ... I only open it, no session is opened, nothing is rendered ...., the fans turn on and do not slow down, again. The rotations per minute rises until about 4000 and the temperatures of the cpu cores goes up to 80-90 degrees celsius. I tried to leave Pro Tools open (but still with no session running) and read and write some mails in Mail. The fans go up to about 5000 rotations per minute after an hour or something. In the activity window I can see that the cpu inactivity is about 90% - so the cpu only uses 10% of its capicity.
When I close Pro Tools, I can watch the fan speed go down until about 2000 rotations per minute - the inactivity of the cpu is now at about 95%.
I first thought that the refurbished product had a problem and sent it back. But now, I got a new Macbook pro (same data, only 512 gb ssd instead of 1 tb) - and got the same problem. What's going on here? I absolutely can't understand why the fans turn on that hard while the cpu INactivity is about 90%! I can't imagine that is a normal behaviour. And I'm wondering what will happen when I start to work in Pro Tools and do some stuff that needs more cpu power...
In any case, the fans make so much noise at about 5000 rotations per minute that I think it is not possible to work precisely e. g. when doing mixes under these circumstances.

Has anyone an idea what' going on here? Could it have somehting to do with the fact that I used a time machine backup from an Macbook Air (my former computer was a Macbook Air 2017)?

I'm really desperate and hope for your help!
Thanks a lot!
Best wishes, Philipp