I found an odd page on Aliexpress upon looking for some ST LRi2K chips. It appears to be a UID Changeable ICODE SLIX.
So I’ve done what any RFID nut does and ordered some.
ISO 15693 UID Changeable + Lua Script by Iceman 13.56Mhz NXP ICODE SLIX SLI SLI S ST LRi2K RFID UID are customizables|Access Control Cards| - AliExpress if anyone wants to have a look.