GA4 & GTM Conversion Setup

I need a one-time GA4 implementation on my custom-built site, using my existing Google Tag Manager container. The only conversion event I want to see in Analytics is a Calendly call booking that has successfully passed our OTP verification step; everything else should be treated as a regular interaction.

Here’s the flow I expect you to wire up:
1. Visitor lands on the booking page, selects a slot in Calendly.
2. Calendly triggers our OTP step (already built).
3. Only after the OTP callback confirms success should GTM dispatch a “otp_call_booked” event to GA4, marked as a primary conversion.

Anything earlier—slot selection, form fill, OTP failure—must not count as a conversion. No ad platform tagging or campaign management is required; this is strictly analytics plumbing.

Please include in your proposal:
• A fixed fee and the calendar time you’ll need (I’d like this wrapped up quickly, but accuracy is more important than speed).
• A brief outline of the approach—e.g., any custom dataLayer pushes, Calendly webhook usage, or additional GTM variables you plan to introduce.
• Confirmation that you’ll deliver a short hand-off document summarizing tags, triggers, and debugging steps so my team can audit the setup later.

GA4, Google Tag Manager, and Calendly experience are obviously vital. If you’ve handled OTP-gated events before, even better. I’ll provide container access and staging URLs as soon as we agree on scope and schedule.