I found the reason why my s20fe stopped responding to the clear view cover. I put on a little steel plate on the back of the phone as a part of the magnetic car mount. my phone stopped seeing the cover, the accesories option disapeard in settings. the steel plate coused this. the phone has 2 hall sensors, one responsible for noticing that the cover is on the phone and the other that recognizes the the cover is either closed or opened. the clear view cover has 2 magnets, one in front part of the cover and one in the back. If you cover the back magnet with something that lowers the power of the back magnet the phone will not see the cover.
in my case I just placed the steel plate of the car mount just 0,5cm below the magnet of the back of the cover.
my problem got solved.
if your phone does not see the cover maybe there is something wrong with the back magnet of the cover and the hall sensor does not see it.
You can alcatel the magnets with a coin.