Framework desktop with AMD Strix Halo [1] are getting there as a viable alternative. Offering up to 96 GB of unified RAM at the moment, so still a gap up to the beefiest Mac Studio alternatives though.
Surprisingly competitive pricing there though. It sucks that they're all priced around $3k in total though (with my Europoor VAT), but it's not as bad vs. Apple as I thought it would be.