New wireframes don't need to be made, because this paradigm already exists in a roundabout way. For many websites that I have signed up for, any attempt to register an already-taken username will present the user with multiple suggested alternative usernames. It's been decades since I signed up for Gmail, but I'm pretty sure that on the sign-up screen you would enter your name, "John Smith", and then your desired email, "johnsmith@gmail", and then when that failed you would be given a list like "john_smith@gmail", "smithj@gmail", "johnsmith2@gmail", etc.
This is the same UI flow as the above, except that it's not based on anything that the user has already entered and it doesn't provide any way for the user to override the suggestions, which actually makes it simpler than the existing flow.
You may be overestimating the typical non-hackernews user. It’s at least as challenging as getting users to use things like 2fa and/or recovery codes.