Can I use the bathtub in a five-star hotel?

The question you asked is not a question at all, brother. Even if I answer that you can't use it, it's because people are unwilling to pay so much. So your problem is just asking others to comfort you.

But ... it actually works. The five-star bathroom is very clean. And if you go to the bathtub like this, even if there are germs, it should be clear. The dirt that looks obvious is just some calcified substances. Relax and use it.