What flooring works best for a bathroom that has an unlevel floor?

Rustic wooden floors are a hot item right now but obviously you don't want to put wood in a bathroom. There is a product out there that looks like wood but is vinyl. They are easy to install and very inexpensive. I know Menards has them. Here is one in grey that is really nice. Check it out and let me know what you think.

Achim Sterling Vinyl Planks 6" x 36" (15 sq.ft/pkg)

Model Number: STP2.0RG10 | Variation: Rustic Grey

I might get some cement board and put that down before you do anything.

What flooring is there now? Vinyl is a great floor material for a bathroom. There are glue down styles and also floating ones too! Im not sure what your subfloor looks like, but in general, a "level" floor isn't too critical. What IS important, especially for a glue-down vinyl, is that your subfloor is really flat. You'll quickly discover that if you go to put down peel and stick vinyl tiles, and there are discrepancies on the subfloor, it won't end up being a solid install. Issues like corners popping up, the vinyl not staying down, or dips and bubbles will occur. So there is, in general, more floor prep needed for a glue-down vinyl, as opposed to a floating system.

https://theflooringblog.com

https://theflooringblog.com/the-importance-of-a-solid-subfloor/

https://thecouturefloorcompany.com