I’m sorry I don’t have the time to read through all the posts here, but for me the problem definitely seems to be on the software side:
I have no protection foil, and the sensor seems to be working (when checking with sensor readout, there is a reliable signal for each time I hold my finger over/ close to the sensor).
But sometimes (just had the problem with a self-initiated call, where I got into the mailbox), the screen still just won’t reactivate.
The power button workaround is a feasible though not ideal solution for me…