My humble limit is 24MP. In my amateur film years, Kodak used to make a great, slow film called Royal. Even had an ISO 25 for a while. Great colors. Rivaling Kodachrome. I'm sure you knew all of the good ones. Right now, I've got enough, being 83 yrs old. Leave the new stuff for the kids, except possibly a full frame mirrorless, so I can take (inferior?) photos with some old German lenses I have. I like that mirrorless can take almost any old lens with an adapter. Doesn't make sense, but it's fun.
If I still used film, I'd be tempted to go larger format.