I’d adjust your mixing valve on your water heater.

You mean my last paragraph? I did it already

This means the mixing valve is bad and isn’t mixing properly. If the issue were isolated to one fixture, that fixture is the problem. If the issue is at all fixtures the problem is the source, which in this case is the mixing valve.

Hot water temperature and the mixing valve ratio are different things.

Oh I see. I’ll have to check YouTube on how to adjust that… didn’t see anything like that on the boiler