It might be hard to access the actual pressure hull from the inside (there's probably insulation and padding on top)
If you use paint, you somehow have to get rid of the solvent in it when it dries, which might be a problem when painting a whole module
I don't know what solvents would do, but I remember that astronauts' bone density loss in space means there are challenges around managing the significant amount of calcium captured by the air scrubbers in the ISS.
https://ttu-ir.tdl.org/server/api/core/bitstreams/f8ca865b-1...
Quoting an ISS astronaut: Today's coffee is tomorrow's coffee.