In broader industry these days, UUID effectively means “128-bit unique identifier” with no other standardization implied. I’ve seen dozens of custom “UUID” designs with no public description in the wild used at massive scales. A major reason for this is that the classic standard UUIDs v1-v5 have a broken design for some use cases so companies invent their own equivalents.

There is nothing wrong with designing a custom pseudo-UUID, and in fact there are often real advantages. The caveat is that you will want to use the same scheme consistently.