I have tried to understand the two main things:  1. Who is involved? and  2. What is the end goal?  Once I understand these 2 things, I then start working towards the middle.  I use Obsidian to define each of the actors, processes, definitions, what connects to each thing…

Janet put together a well thought out answer. From my (limited) experience, what she said, I agree

Are you still looking for a solution. I would reach out to martyn@nymbl.app

Don't do Airtable, too many limitations. Caspio also has issues. Reach out to martyn@nymbl.app - they can help you. Personally I use them (Nymbl) with Zudy Vinyl. 

It depends on how large you think the application will become and what complexity you want to build into the system.  I, personally use nymbl.app to build out my platform. 

First thing that matters is your current and future needs. There were lots of systems I looked into that would have different issues when I looked into scaling out. Sometimes it was number of records, other times it was speed, and other times it was lack of flexibility…