Your boss texting at 10 p.m. doesn’t mean you owe an answer at 10:01.

A message arriving does not create an obligation on arrival, and most of the pressure you feel is about the hour rather than the content. Managers send things when they think of them, which is often late, and thinking of something is not the same as needing it dealt with. Replying instantly at night sets the expectation for every evening after this one.

Unless the job genuinely involves being on call, and some do, read it in the morning and answer then. Real emergencies come by phone. If it becomes a pattern, raise it while you are still new enough for that to be easy.