Power button on console is jammed

While the bottom panel is off, see if you can gently push down on the power button's clicker (tiny amber disc). I find that the T9 security torx driver used to remove the bottom panel makes for a wide implement with which to push it. If there's no pronounced click, you can just replace that TSW-001/2/4 board with any of the variants. You can find them for $3-4.

If it seems clicky enough, then it's the power/eject button. I had one recently unseat while cleaning the bottom panel. It took me a minute to figure out how to seat it back properly, but it's pretty easy, even without any tools. I was once placing an order on aliexpress and ordered a few different PS4 power and eject buttons, so they can be had if you look for them.