Suggestion of Customer Onboarding.

Our Saas platform is aimed at Freelance developers and agencies as its target customers. We like to have users who use business email for signing up, but when we surveyed some of our prospect groups we understood that we may need to provide free mail signup (Signup using Gmail or yahoo) But we don't want it to use for system spamming. My question is, will it be wise to have an OTP validation for Freemail users before signup so that we can validate. Or will it turn off the users in signing up with that extra process?