Hello and welcome!
A couple things about this:
EMV allowing implants on their networks as far as I know isn’t exactly in the “near future” stage, so I don’t think that’s something you should get your hopes too high for.
At the moment, there’s only one pre-made implant that could actually handle payments, and that’s the Vivokey Apex Flex, the NExT will never do payments.
You could however look into a payment conversion, which has its own benefits and drawbacks
This depends on the type of chip you get, for example the NExT is actually two separate chips, one of which can be programmed with your phone and the other takes something like a proxmark3
As Amal said above, these chips aren’t really clone-able. If you can convince your school to let you enroll a new tag, you could use a FlexDF2 or xDF2. Though, I don’t think I’ve ever actually heard of anyone getting permission for that oddly enough.
And neither of those chips could do payments either, I believe