You might want to have the mixing gasket replaced in your shower. It’s responsible for mixing hot and cold water in your shower and can be the culprit of your shower being too hot or too cold. They have a limited lifespan and need to be replaced eventually
Sounds more like you dislike bad water. I think well filtered water at this point is table stakes.
Especially if you live in the US where you either have a leaf service line or more PFAS than you’d believe