My current one is in P0, yes. I had no idea there were other places it could go on the same hand.
I’ll be more specific. What I would like is one with a “lot” of storage space for NDEF, so i can save multiple records. I would like to save medical emergency info on it, organ donor information, a shareable contact card, maybe some encrypted important passwords, stuff like that. If I ever feel like buying crypto for some reason, I would want to put my crypto wallet on it. So, lots of space would be cool. I would love to try writing a video game whose binary fits onto it 
I would also like to use it for access control for my own place, so no need for clonability there. If I do want to clone access control, I do have the old implant, like you said. I don’t think I need a 125khz chip for that, right? So a single chip implant is fine.
Payment is not my priority, so let’s ignore that for the recommendations.
It should be compatible with both Android and iOS / iPhone. In terms of placement, I would prefer a place where it doesn’t protrude from the skin much. Blinky seems like a cool party trick, so if there is a blinky one that also fulfills most of the above, I would love that. If not, that’s okay, too.
Apart from that, I don’t really know what other types of implants there are that are as safe as these NFC chips. The magnet seems cool but not really something I’m interested in. I’m enthusiastic about biohacking but, as you can tell, horribly uninformed about it
Again, really appreciate you taking the time to help me out, I did not expect that at all!