Hi @whynot thanks for reaching out!
Currently, we do support some url customization, as noted here: Custom URLs for web apps | Retool Docs
so you can have a /deals app. However, currently you'd have to pass the specific deal info as a url param instead of including it in the path dynamically
You could have something like:
Main app: https://portal.domain.com/app/deals
Drill down app: https://portal.domain.com/app/deal?id=51
We're working on some projects related to multi-page apps, so I'll leave this open as a feature request