MicroSD card not recognized anymore by Android phone
Is there an overheating issue in the phone/card combination, maybe? Some other compatibility issues (timings/delays) might play into here.
(I had a similar issue with a 128 GB SD card on a Samsung s5mini, the card disengaged during use)
My solution was to exchange the card for a different (well known) manufacturer/type.
You could try doing this temporarily at first with a card from somebody you know.

You could try testing your SD card for hardware errors on PC with H2testw (download source with high reputation) app,
no formatting needed. Just reformatting the card doesn't force the storage controller to actually access higher sectors on the card, so this doesn't give information about the card being physically ok.