I am building a sort of centralized Supabase database. One single database that holds (non-critical) data of many businesses that is going to be shown in the frontend.

For each business I have a specific authenticated user and a clients table which connects their UUID to their business. I have a dashboard which dynamically, based on user, gets their business tables and lets them perform CRUD operations on them. All the tables have RLS implemented. The main purpose of the dashboard is to have a custom solution for my clients that is easy to understand and relieves me of the trouble of changing their data.

What API call setup would display this data on their respective front ends?

The approach should handles security while being quick to implement, because I build front ends almost from scratch each time. The front ends will only fetch the tables. I don't want to build a back end; everything should be serverless, handled by Supabase.