A uuid is a 128b number with a specific structure. You can encode them in base32 if you want, there is no need for any sort of conversion scheme.
You need to convert it to perserve the timestamp info correctly so that a ULID library reading the base32 format would reproduce the same timestamp.
Now someone should make a UUIDv7 -> ULID adapter lib that 1:1 translates UUIDv7 <-> ULID preserving all the timestamp resolution and randomness bits so we can use the db-level UUIDv7 support to store ULIDs.