middle board proxmark’s are monsters and have sketchy at best quality.
lf bringing up indala is totally somewhat normal. it’s indicative of signal noise so you can disregard it (the output when you get indala tells you as much.) your implant doesn’t even have LF as it’s an xNT.
as for HF, do hf 14a reader -@ to continuously scan for iso14a chips. while it’s doing this take the edge of the hf antenna and hold it parallel to your implant until you get consistent reads, then do hf mfu info
i understand you are likely just wanting to get your implant to scan with the proxmark but if there’s anything you’re planning to do with an xNT you’re better off doing it with a phone. it’s a very basic chip in terms of functionality and there’s nothing the proxmark can do that a phone can’t, and the coupling will be easier with your phone. download NXP tag info.