Betta Fish: Is this intense glass surfing normal?

Hi everyone, my betta I got about a week ago glass surfs along the front of the tank all day and all night. Sometimes it gets pretty frantic too. I can’t tell if I should be worried. Things I’ve tried:

Adding tannins
Lowering the light
Adding lights around the tank to reduce reflections
Removing background, adding background
Increasing and decreasing temperature

Parameters are 0 ammonia, 0 nitrite, about 10 nitrate, 6.0 PH. It’s a 5 gallon tank with a heater and filter, and a tiny air stone. she does this even when the tank is dark and all lights are off. I think she does it while I’m not in the room too. Is she bored? Wanting food? Excited? Stressed? She only does it at the front of the tank, never on the sides. I’m worried she’s gonna exhaust herself from doing this. If it’s boredom, what can I do? I thought about adding a few shrimp for her to interact with, not hunt exactly but distract her from constantly swimming back and forth.

Idk if you can see in the video but she also does this weird thing with her mouth while she’s going crazy, it almost looks like gulping. Any ideas or advice is much appreciated.