Is there a way to "pay what you wish" like some other offerings? I'd love to pitch in some money for the dev, but don't want to go through the hassle of subbing on Patreon then cancelling.
Not here, no. Itch removed the ability for devs of NSFW content to collect any form of payment on their site last year due to the Collective Shout "controversy". I believe the only options to give Cosy Creator any funds now are through Patreon or Subscribestar.