I see how it can replace 80% of glue in my typical project. However I am not sure how to handle the remaining difficult 20%. Particulary where to put the busine

I see how it can replace 80% of glue in my typical project. However I am not sure how to handle the remaining difficult 20%. Particulary where to put the business logic. I don't want to have all my business logic in database. I don't want to write all business logic in SQL. SQL is not good language for this and the tooling is suboptimal: editors, version control, libraries, testing. Is there a way to define stored procedures and triggers in some host languge (as with SQLite)? Or is the recommended way to add extra API handled by language of choice? But I don't want to do the same things in two different ways (i.e. querying by PostgREST and querying the DB directly)