Just another data point;
Both my NExT and xMagic are installed at what I would personay consider a medium depth, just deep enough to not see easily when the skin is stretched.
Neither is finicky with anything LF, and in fact have worked with everything that I have tried them with (given the correct frequency). However, it is worth noting that I get slightly more consistent reads with the xMagic. Both will read from a PM3 Easy maybe 5mm away, but when touching and as perfectly positioned as I can manage, I can get a read 19/20 times with the xMagic and maybe 17/20 times with the NExT.
It is worth noting that my NExT is under thicker skin (left wrist alongside Ulnar), so I think this variable explains the differences I’ve seen in my implants.
(Also, location of my NExT is lovely, I rate it 4 stars if anyone has already filled all of their P0-P4s)