I believe it's still possible, but subject to the absurd visa/mastercard adult content restrictions?
I own a few on here and they appear to still be possible to purchase, other than the ones that abandoned the platform :(
AHITR made this post about monetized adult games being deindexed. They decided to make a separate listing for the paid version, so the free version could remain indexed and discoverable. https://zanithone.itch.io/a-house-in-the-rift/devlog/1489380/ahitr-itch-premium-...