Wall treatment for imperfect bathroom walls

I have two bathrooms that I am remodeling in my house. The walls aren't perfect due to a previous owner remodel, they were wallpapered, but upon removing the wallpaper the surface isn't paintable, some of it is textured, some is smooth, patched, etc.

I am looking for some ideas on wall treatments. I'd like something unique but subtle and not uniform, not your typical roll on or spray on wall texture that home depot sells. The colors will likely be greens & greys (very earthy), 6' distressed grey tile floor, birchwood minimalist cabinetry (not enclosed), and white porcelain.

Any ideas? Paneling? Paintable textured wallpaper? some sort of hand troweled spackling finish? something else I'm not thinking of?

Thanks