Hi there,
Ok then, Sounds like you HAD a plan… but would also agree @msfujino, I say again the cell traffic or the 5G is an issue (filter) the noise you inject can you get more specific Freq. ? Being familiar with the Sx1262 front end in that depth is more a manufacture realm of questions anyway.
(-105dBm @ 5dB ) is pretty good at distance so I feel like the receiver being on/open always is doing something that makes it susceptible to what ever it is, I don’t at this point have a next thought. 
Keep at it though 
I think your in the right ballpark. 
HTH
GL 
PJ 
Sorry I just did have a second one, Could you Sync everything timing wise and not leave receiver open always? “myllast noodle to the wall”