Bubble Expert Needed: Architect Diagnostic Platform Foundation + 1 Reference Build

I'm building a healthcare consulting platform featuring a suite of interactive diagnostic assessments. I already have the full design system and working front-end instruments, built in vanilla HTML/CSS/JS (no framework). I'm looking for an experienced Bubble developer to architect a clean, scalable foundation and build one diagnostic end-to-end as a reference I can replicate myself. What's Already Done (No Need to Redo) Complete visual design system and branding Working example instrument (scoring logic, report, contact wall) Detailed data-capture specification (the exact payload each assessment should store) Scope of Work (Fixed Price) Design and implement a clean Bubble data model (Diagnostics, Submissions, Users) optimized for easy export and cross-diagnostic analysis User authentication + contact-wall gating Stripe integration for one-time individual diagnostic purchases One full end-to-end diagnostic: embed my HTML/JS instrument → capture results → store in database → gate → payment flow Recorded walkthrough + clear documentation so I can build the remaining diagnostics myself Explicitly Out of Scope (This Phase) No subscriptions, team accounts, or multi-tier pricing — keep the payment flow simple Not a finished multi-tool product — I'm buying a clean foundation + one reference build I can clone Important Notes All accounts (Bubble, Stripe, domain, etc.) remain in my name — you'll be added as collaborator only Fixed-price, milestone-based payment I'll request a small paid trial task before committing to the full project To Apply, Please Reply With How you'd handle embedding a custom HTML/JS instrument in Bubble — specifically, both passing its results into the Bubble database and the reverse: triggering a Bubble workflow (save + payment gate) from inside the embedded instrument. This in-and-out data flow is the crux — generic answers will be ignored. Links to 1–2 Bubble apps you've built that include real data models and payment flows Any concerns or suggestions about the plan above — including if you'd push back on the embed approach itself Bonus: how you'd structure the data model so cross-diagnostic analysis is easy later For the fixed scope above, please propose your own fixed price and rough timeline. Looking for someone experienced, communicative, and patient with a founder who wants to learn and eventually maintain the app.