I usually use TagInfo for advanced reading and NFC Shell for advanced writing of HF tags (both Android apps). I usually don’t bother with HF on the proxmark because it’s seldom worth the effort (other than MIFARE). You absolutely need the Proxmark for LF tags though.
I can help you with NFC Shell commands if you want, though you seem to want to use the Proxmark. The community at large should be able to help you with proxmark commands.
Two suggestions just for clarity. I would edit all your references to the xEM and xNT to just say NExT (HF and LF side). While they have the same chips, the NExT is pre-configured while the xNT is not, and they have slightly different antennas because of the form factor. I would also hesitate to use the term “UID” for LF implants. Just ID would be better. UID is reserved for 7 byte ID HF tags that are truly unique.