It's funny because I've had this one particular issue with two Asus routers that I manage for family...

They use this plunger power button design, you push the button in and it toggle locks in to place, the problem is that after a few years whatever mechanism retains the plunger fails and it always springs back and keep the device from staying on. So far the solution has been to cram a paper clip down the housing to hold it in. I just find comedy in having to apply that fix twice.