Its nice that you want to. That means you want to sell. The problem is this is copyrighted and you'll lose your revenue channel, and be unable to sell again, you'll be lucky to earn $50 before you get reported by the community.
I suggest you look at ai artwork,and trace it, (what i do for my merch designs) so it doesn't fall foul of quality standards. I used to sell lots of tees, and my best ones where just text and a clipart graphic. (way before any people using ai) Screw disney, they aren't that special, compared to the things you can describe and draw yourself.
You have wojaks and mountains of memes, and any special trend that is in the spotlight to choose from. Just keep uploading.
I would suggest rather than etsy to start, you look at POD markeptalces. There are about 5 free good ones, and you can make your bread and butter there, to pay for you to list on bigger places your best designs say on etsy/ebay.
Good luck. Just don't get banned, this isn't easy work to just register an email, and start a new account. You'll need a new pc/device and ip address for any marketplace you screw up on. So check your slogans against the copyright trademarks search engine regularly.