Just chiming in here a little late to add my own experience with this issue on my 2018 X5 (F15). Yesterday my key fob remote wasn't being detected unless I held it directly against the steering column. As soon as I started driving, the system warned that TPM wasn't working, and at the same time, I noticed that my phone would no longer connect via the car's Bluetooth. Tried the other key fob, same result. Replacing the batteries in both fobs didn't help.
Based on the advice I found in this thread, I removed and reseated the fuse for the remote control receiver, and it immediately fixed the problem for me. The fuse I pulled was in the fuse box in the passenger side foot well, shown as #19 on the diagram here:
https://fuse-box.info/bmw/bmw-x5-f15...uses-and-relay (note that it's the top one shown as #19 - not sure why this diagram has two fuses with the same number).
Hopefully this will help someone else avoid a costly trip to the dealership. Cheers!