Yeah I've also tried using AI to generate a few ideas, but in most cases they're not particularly good. Granted though I wasn't using ChatGPT and instead running a local language model (which are currently worse overall than ChatGPT).
For me, meme ideas just randomly pop into my head. Like I'd be drinking coffee and suddenly have a thought "Hmm, is there any scene that they have someone drink something? Or is there a quote I can use that would work with coffee". Or watching some movie/video and think "Haha, wouldn't it be funny if Sam was there". That sort of thing, if an idea catches my interest I try make it, and often it's a hit or miss.
So just try throwing stuff into GIMP or Photoshop and see what sticks.