Our development team has been using Okta for almost two years now, we are close to doing a beta test with real customers (most of our users are in testing environments).
Our company has plans to use Auth0 more. A different team has been seeing how they can convert more over to Auth0. Our issue is do we proceed with Okta and move to Auth0 later, or just move over to Auth0 now before we have onboarded customers?
You should ideally start with feature parity and form a migration plan before proceeding with moving customers over. Ideally, since you have context required on all the features, you would need to make sure the implementations in your Okta instances are supported in your Auth0 instances. The assumption that they are both the same would be an initial roadblock to migrating users.
Ideally, this is a platform migration; even if this sounds like a move from Okta to Auth0, there are many specifics that might need to happen on the Okta side to even gauge the difficulty.
So, make a migration plan and check for feature parity, and then raise a customer support ticket or reach out to your Okta and Auth0 CSM to see how to go from there.