In my future bathroom, I tiled halfway around. But that was only partly intentional, as it resulted from the room layout and the arrangement of the sanitary fixtures. The shower is not tiled up to the ceiling because the ceiling is over 3 meters high. The tiles are about 2.4 meters high.
In my rental apartment, I only tiled the shower up to the ceiling, behind the sink and behind the toilet. Yes, the floor too, of course.
There has never been a problem with water on the walls. I always wonder what could really happen there. You only really need to tile where there is splashing water and where you want to clean quickly and easily (toilet/sink).
Water-repellent paint would then be latex paint? But I don’t know if it is so wise to use it throughout the whole bathroom and I also suspect that the paint inside the shower is not the best option? Generally, people have moved away from making a bathroom "waterproof" and nowadays only make it waterproof in the direct splash water area and the floor.
Beton Cire, is it also resistant to cleaning agents and scrubbing? I suspect the sealant will wear off at some point and if then sharp cleaning agents come into contact with the concrete, there will be white efflorescence? I am skeptical whether this is the better solution in the long run.
Vinyl flooring in the bathroom, if you want a wood look, is certainly not a bad solution. As far as I know, you have to glue it down, but that should not be a problem. I would not use real wooden flooring in the bathroom, it probably won’t last in the long term. Ceiling and walls that do not get direct moisture should not be a problem.
I have never really looked into it, but for showers there are also plastic claddings that are completely seamless. It's basically a plastic wall of 2x1m (example dimensions) that is mounted/glued to the wall. You find that with cheap showers, and there sure are higher-quality versions as well.
This way you could glue vinyl on the floor (there are many designs) and look for plastic cladding on the walls in the splash water area. I would recommend bathroom showrooms as the first point of contact. The possibilities are so extensive today, I am sure there are countless solutions for a bathroom without tiles.