I'd quit too, but unlike OP I'd focus more on my designer job and less on this hobby if I have 0 skill in marketing.
The game is ... ehhh 5/10 , there's no new mechanics in it which you haven't seen in other games so the dev is just being a little shit when he says he got his ideas stolen since he has no new ideas to steal. Actual good ideas worth stealing require talent.
Also somebody who already has a good paying job really doesn't belong in the porn industry, they're better off putting that huge amount of money into stocks,options,assets,crypto which doesn't require effort & time.
Game development itself even without the porn attached to it really isn't a good place to make money. It's far too competitive.
Game is still receiving only $9.8/month because OP has 0 skills in marketing and refuses to learn any.