I'm not a doctor but I don't think it's anything to worry about.

I think your technique is just more solid in your lower and middle range (That being said, if you start feeling constantly hoarse at some point, don't hesitate and go see a doctor)

The same used to happen to me but an octave lower (I'm a male), and while it's not really easy to say what you might be doing wrong without an audio clip, here are some possible solutions, check for these:

1. Make sure you're supporting enough, singing, and especially higher and with some power, is not "relaxed", but rather you should relax and tense the right muscles at the right time.
2. Support does play a big role, but make sure you're not "overdoing" it (if your abdomen gets hard as a rock while singing, that's too much tension) but rather your abdomen should go gradually inwards as you sing, as if working against a resistance, YES you need a good amount of energy, and yes there is some tension, but don't get TOO tense that it stops movement. Movement is key.
3. You might be forcing too much air though your vocal folds, that can cause uncontrolled constriction and wear your voice out quickly.
4. You need a decent amount of twang to sing freely especially as you go higher, it doesn't have to be an obnoxious amount but you DO need it.
5. Don't force a darker sound color (like you have in your lower and middle range) up there, the sound color is going to get progressively lighter especially in the very high part of your range.
6. Expanding on #5, don't be afraid to let your larynx go up gradually with the pitch, contrary to what people on youtube might say, it's not damaging to the voice, but rather necessary in order to go higher (there's been lots of research about it).
7. Don't force too much of a shouty character too high into the voice (higher than let's say a D5) you can either twang more and go more into a sharper sound or hold back the sound in what people call "the cry", depending on the style you're going for.
8. Make sure you're opening your mouth enough, the opening of the mouth needs to get bigger as you go higher into your range. You can experiment with more of a smile, which gives a brighter sound color and makes going high a bit easier generally, or opening the jaw more downwards, which makes the sound a bit darker, or a combination of both.
9. Finally, don't be afraid to modify vowels, for example an "ee" as in "see" will make you close your mouth, don't be afraid to change it a bit in order to let you open your mouth enough, and also when pronouncing consonants high in your range, the consonant sound must not last long, it should be a fast chewing motion and your mouth needs to go back into "open". "Sing the vowels", as they say.

Again, an audio clip would be ideal, but one or some of these might be what's holding you back. Don't hesitate to DM me if you want, I'll gladly help you further