RC + Zapier + Stripe

Hello RCers! We are trying to build sign up flow(not for us, for public users to set up their own workspace) plus payment page with Stripe.
Our goal is to build an admin page as in attached photo(RC cloud silver plan)

RC HQ said we can use Zapier + Stripe integration for a very simple MVP building.

But there is no trigger like “new workspace” nor “new user” in above integration instruction. Without RC trigger Zapier cannot send data to Stripe payment API.
We’re stacked.

Do you know how to build a very simple sing up + payment page as our MVP?
I mean RC workspace is not for us. Third party new customer needs to signup and create their own workspace (& pay) like RC cloud silver plan.

We really appreciate your help!