I am not sure if your problem and my problem is the same or not, but for last 6 months my keyfob was losing battery every 5 days. I called service, they asked all the normal troubleshoot questions, 'how far do you keep your keyfob' 'try removing the key from your profile and adding it again' etc. I did all of this and the problem still persisted, i got some ugly faraday cover for the fob and the problem still persisted. I finally gave up using the key fob entirely.
2 weeks ago, my mobile key stopped working as well, called service, same thing, soft reset, remove mobile key from the profile and add it again, well it wouldn't add again at all. The car wouldn't lock/unlock, i had to manually go in the app and lock/unlock the car. Mobile service came, turns out front node antenna was not communicating with whatever it had to communicate with.

Supposedly there are 5 antennas in air, and if the front one goes down, all go down apparently. The front antenna was replaced, the keyfob and mobile key both work now.
For the last 6 months, i felt like a dummy thinking i don't know how to use a stupid keyfob or don't know how to change the battery because how come i have to change the battery every 5 days. I used to use Duracell, lucid engineers recommended Panasonic battery so i got Panasonic, i was ready to climb a mountain, go on a pilgrimage, if that made the keyfob work. Turns out it was the front antenna.