Right, so I think this is a Supabase thing instead of a WeWeb one, as I can see that you’re familiar with objects and making dynamic elements in the editor.
https://supabase.com/docs/guides/database/functions
What you need is to have your server push a join of your datasets to your front-end. I am not exactly familiar with Supabase, but you can use SQL functions as per the documentation above.
Another shortcut could be to follow this thread from Joyce : 🎯 GET Data from Supabase. Look at the Advanced Mode in WeWeb which allows you to make custom queries to your supabase database.
Hopefully that can send you in the right track 