Seems that a broken power button is common with this case and looking at the flimsy original I can see why.
This simple replacement will keep my case out of the garbage. Hopefully yours too.
I recommend printing in PETG for the flexibility, although I tried a PLA version and it was Ok.
Attach the new power button using the existing screws then use a heat gun or flame to soften the plastic and shape it as shown in the photo.
Original Fusion 360 design file is included if you need to adjust something.
The author marked this model as their own original creation.