How to share a fan robot with LEGO?
It looks like you don't quite understand how those robots became supported by Lego.
You see, EV3 was released in 2013, and they've supported only 12 fan robots. That's not a lot, and if they were still accepting fan robots for years they definitely would've had more robots on their site. I have an unofficial book by Laurens Valk about EV3 programming, in this book he has instructions for about 3 more of his robots. Yet none of them are on the site.
Why am I even mentioning a Lego fan and his book? Because this page says that the race truck was designed by him. That's the only model he made that's on their site, but there are some people who have had multiple models of theirs accepted by Lego. They are Martyn Boogaarts and Kenneth Madsen. And I could've sworn that I saw a video(s) somewhere where they were interviewing the designers of these robots.
Looks like they were only accepting fan robots from skilled EV3 users.