One of those Membership/Subscription questions again

Hello,

New to Webflow, but in terms of web design I’d pitch myself as an advanced learner, youthful intermediate.

I’m looking for some guidance as to ways to approach an idea.

Backstory
I run a healthy business in the UK and help other small businesses in my spare time.
I looked online for a free-to-list website I could list some basic info about my skills so that business owners who were looking for a business coach could find me.
I found plenty of monthly sub / professional business coach sites, but nothing free.
So I’d like to make one.

Rough requirements spec
Site lists multiple business coaches with details trawled from publicly available sources,
Each coach has their own ‘profile page’ on separate URLs
Visitors looking for a business coach can fill out an enquiry with details of their location and coaching skills they require
Free level accounts list business coaches basic contact details
Free level users can claim then upgrade their accounts to ‘Pro’
Pro level lists all their details, qualifications, professional memberships, biography etc
Pro accounts are listed higher in the search results, appear first on the ‘locations’ page, first on the 'skills page, etc etc
Pro accounts are sent Visitor enquiries 24 hours before the free levels gets sent them
Pro accounts pay monthly sub through the usual payment processing platforms

Stream of consciousness
The guys at https://www.unicornfactory.nz/ seem to have something similar - I’ve been in contact and they’re thinking about making a how-to video which would be amazing
Should I use Firebase to manage users?
How should I manage user accounts?
Memberstack doesn’t seem quite right for the accounts/membership requirements
What about auto emailing Free and Pro users. How would you do it?
What’s the best approach to this project?

Thanks for your thoughts in advance.


Here is my public share link: LINK
(how to access public share link)