UUIDv7 has all the advantages of UUID, plus sortability, plus an embedded timestamp which can replace your "created_at" thus reducing the cost aspect. It's also

UUIDv7 has all the advantages of UUID, plus sortability, plus an embedded timestamp which can replace your "created_at" thus reducing the cost aspect. It's also soon becoming an official part of the UUID spec. In fact, if your created_at is indexed and you can get rid of it via uuid7, there is practically no difference in terms of table size. The size cost is solely on foreign keys.