YMMV but Gmail hasn't been that bad for me. The only problem I (knowingly) had was with a newly registered domain and mails still at least went to the spam folder there. Microsoft has been much more annoying, punishing you for bad IP "neighbors" that you have no relation with. Of course I don't know if all my mails get delivered since I don't do any tracking, just relying of voluntary in-band or out of band replies / receipt confirmations. And being based on black box heuristics (and "AI" lol) there is no guarantee that my experience with Gmails spam filters is the norm - but Gmail rejecting half of self-hosted mail seems a very pessimistic estimate.

Still, just citing numbers for how much spam they blocked is (deliberately?) only showing half of the picture.