The thread about summarizes my experience when my 12v was giving warnings. I procrastinated and procrastinated hunting around for a drop in replacement. Mine, fortunately, was the revised location (2015 85D) which meant a few bolts are all that stood between me and removing the frunk liner to access the battery. It hurt internally that I had to call in for service because I could not find a replacement. Then again, anything that was a close replacement was about $150 anyway.
Finally got over my "I can fix this myself and save money" mentality and setup a mobile service appointment (after weeks and the car started exhibiting charging issues) and in less than 2 days the ranger showed up, swapped the battery, did some update/checking with his laptop, and then left. $175ish, IIRC, and it was taken care of in my own driveway without me having to do anything but pull the car out of the garage (super convenient as I'm working from home).
Definitely worth setting up a mobile service appointment if they can get out to you. My nearest service center is a bit over an hour away and they have mobile rangers in my area frequently.