This is by no means something new. All my Macbooks had this issue. My 2011 Air had it. My 2015 Pro had it. My 2018 Pro had it. And now my 2021 14" has it. That's the price we pay for thinness.
The only "solution", if you can call it that, is to put a sheet of tissue, like the one it was supplied with, or some other kind of protector, on the keyboard each and every time you close the lid. But I can't be bothered to do that. I'd rather live with the ghost imprints and just clean them from time to time.