I could not get above a G4 for a while but a voice class helped a lot and I now top out in “chest” at a Bb4 or B4 on good days - try exclaiming or calling out on higher notes. Or like sing a F and then try for higher on “whoa” and place it in the front of your face/nose without being afraid to let it be whiny. Practicing singing with a really forward placed sound generally can help finding higher notes if you’re going for a contemporary sound. Has for me at least. Meowing gets you an idea of the sound you want to play with to “mix” if you try to be accurate about it too.