@Inma Thank you for posting your query on Microsoft Q&A.
From my understanding, you are looking to extend the backup/snapshot retention policy period from 7 days to at least 30 days in Hyperscale sqlserver db, and also want to know another supported tool to implement long term retention backups in Hyperscale (bacpac, export, ADF pipelines etc) at schema level or table level.
Our product Group is planning for a public preview for short term retention (PITR) greater than 7 days (up to 35 days) this year. As far as I know, there is no supported tool to implement LTRs backup at schema level or table level.
Regards,
Oury