Have single FOB#2 and range is suddenly terrible

Hi all, first time user from Chicago. I have 2010 MDX purchased as a certified pre-owned in 2012.
I lost the #1 FOB over 3 years ago, and have been using the #2 successfully ever since.
I replaced the battery in #2 a couple years ago when the range went down and it worked flawlessly since then.
About 3 months ago, the range in #2 plummeted again (though much more suddenly this time) and I figured it was a battery issue.
I can only stand close to the driver or passenger window and the lock/unlock feature works sporadically - I have to point the FOB at the driver seat (I think the receiver is in the fuse panel in upper left driver leg area). The FOB-under-the-chin method does not noticeably improve the range.

So I replaced the battery (CR1616), and no improvement.
I pulled battery and put a new one in after checking both batteries for voltage, they're both strong (~3.2V). I also verified the contacts in the FOB are strong, in contact, and gunk free.
Still same issue.

I've read that re-programming is a possible solution.
And I've seen that the receiver might replacement, though I don't understand how that make sense, because it DOES work, if just unevenly.
Do FOBs get weaker over time? (besides battery issues)

Can anyone recommend next steps?

Thanks!