I still believe the stored procedure route has merit. It's harder since most available libraries are built around the idea that the frontend has full access to the database. A frontend in (insert favorite frontend lang/framework here) and a backend in Postres using stored procedures could work quite well.

Unfortunately, the 'meta' is all about frontends with full backend access, so that's what I'm learning alongside other stuff.

Not sure if you've looked into either of postgrest or postgraphile, but I feel like those tools may be right up your alley. Rather than have your app layer generate SQL via an ORM, these tools instead generate your app layer based on your database schema, functions, etc. Postgraphile (generates graphql APIs) is particularly friendly towards frontend-heavy web apps.

Thanks for the recommendations, I'll check them out!