A form fill is not a lead. A booked call is not an opportunity. An opportunity is not cash. If the objects change and the keys do not travel, the conversion rate is a ratio of unlike things.
Write the steps
Name each object in operating language. Capture identity at each step. Keep an unknown bucket. Then the rate can be argued with, which is the point.
What usually lies
Platform conversion rates that stop at the form. CRM win rates that ignore unmatched payments. Funnel charts that restart the person at every tool. None of those is a lie about competence. They are a lie about the object.
A usable rate
Enquiry to conversation. Conversation to enrolment or close. Close to cash. Each with coverage: how much of the next step still has no key. Optimisation waits until those rates are reproducible.