And welcome to the community!
From my first read through this, it sounds like having a doc with your questions set up the way you want to send them, and just naming it something like “Templates” would work. Each page can be it’s own template. Then if you create a new doc for a client, you can just copy a the pages you need over to that doc, or make a copy of your “Templates” doc and rename it for that client.
The other answers above have to do more with compiling all client information into one place, but if this is a collaborative environment for you and each client, I think one doc each can work just fine.
Personally, I create a “Templates” folder in my Workspace and keep my doc setups there. Then I just copy those docs and rename the new ones when I need them.
Does that sound like something that might work?
I’m happy to elaborate more too.