The maintainer of the Mac package reports:
“As for Apple Silicon, Gramps 5.1.3 runs fine in Big Sur using Rosetta2. I had to return the Developer’s Transition Kit a couple of months ago; at that point there were a couple of dependencies that use assembly and had not yet been ported to Apple Silicon so I wasn’t able to build a Gtk stack. I was holding out for the much-rumored “pro” Apple Silicon, but WWDC passed with no hardware announcement so I just ordered an M1 mini because the MBP I’ve been using the last several years for macOS Developer’s Betas is too old for Monterey. That won’t allow enough time to do more than check that the Intel build runs OK with Rosetta2 (though I have no reason to expect that it won’t). There are now enough M1s floating around that I hope that the assembly bits have been written and I can build a Gtk stack.”
So the answer is currently “yes, but not natively”. However, she can expect a performance boost in the near future.