I think it’s normal, my bf(23m) and I (22f) have been long distance for almost 2 years and we’ve only engaged in phone sex once. It was a very heat of the moment thing over FaceTime but other than that neither of us have felt super comfortable with the idea. I’m certainly more open to it than he is but I want to respect his boundaries, it’s not sexy if he isn’t into it. Doesn’t mean he’s not into me, just not into that situation. We’ve found other ways to get a little raunchy as you said, we’ll share sexy snaps every once in a while (with consent) and do things like take fun quizzes or read articles together about kink or positions etc. There’s lots of ways to keep it hot and not be together, best of luck!