if you can sit in it, it's probably fine.
I'm a big bath taker, with hot water and I have not adjusted anything because I am pregnant. The water cools down after a bit anyways, so it's not like a hot tub where it's constantly hot.
This. If you can sit in it, it's fine.
The issue with hot tubs is that you may get in and the water will be fine, but the temp can increase without you knowing it. And that can raise your core temperature, which is bad if your core temp is over 100.
With baths, the water temperature will naturally decrease over time. So, as long as it isn't too hot for you when you first get in, you should be okay.