I desperately wish people would start actually reading the AO3's TOS before confidently making 'user guides' to the AO3 that are just blatantly, flatly wrong.
Yes the AO3 has banned content. They do not allow anything that's illegal under US law - though US law, importantly, does not ban fictional depictions of things - and they do not allow any commercial content. That includes your ko-fi link, or mentions that you do fic commissions. If you do post fic commissions to AO3 and want to mention the commissioner, the fic is a 'request' from the commissioner. This protects the AO3 and you from copyright law.
No the AO3 is not 'a creative fanfiction archive'. It is a fandom archive. Your meta, insights, and theories are absolutely welcome and encouraged there. AO3 also encourages you to post other types of fanworks, like fan videos, podfics, and art, but unfortunately isn't able to natively host those like it does text, so fic has kind of become what it's known for. That absolutely does not mean that other types of fanwork aren't allowed, or are discouraged by the site culture! Anybody who tells you otherwise is just plain wrong!
And another thing:
IT’S AN ARCHIVE - A STORAGE SPACE
THERE IS NO ALGORITHM
IT’S A LIBRARY, NOT A SOCIAL MEDIA SITE
So… (sigh) TAG YOUR FICS APPROPRIATELY AND PEOPLE WILL FIND YOUR STUFF.
That’s it.