Let communities approve accounts registered through their invites

Problem

I may not be up-to-date with the current systems in place, but as far as I understand, it is more or less that all users are required to be approved by the instance operator(s) before being allowed access to the Communities within. As a larger-scale instance operator, I want to be able to limit the flow of incoming account registrations, but allow Communities autonomy over the users that they take in. Approving influxes of account registrations for a specific Community, for example, would be cumbersome as an operator to manually approve, additionally having to communicate with that Community's leadership to weed out any malicious actors trying to squeeze their way in the pandemonium. The job of vetting those accounts would be better handled by that Community, as they have a more concrete expectation of what users should look like.

Proposal

An alternative user approval method: When someone registers for an account via an invite link to a specific Community, the approval of that user should be deferred to the administrators/moderators of that Community, rather than the instance operator(s). In other words, for community invites, I am suggesting the registration screen be overhauled to a customizable application form. This way, Communities can get the information they need to make a better decision when they are the ones vetting new accounts. In turn, operators are more hands-off with the vetting process where they aren't necessarily the best source of judgement.