It's almost like you didn't even try to find it. It's stickied in the section.
https://osbot.org/forum/topic/93776-account-selling-read-before-posting/
I've traded quite a bit of gold over thru a mule to my main and none of them have gotten banned. If it's only your mule getting banned I'd lean more on it being the proxy
There are no "best" settings. You have to experiment and see what works best for you. Some proxies work well, other proxies will get you banned instantly, etc etc
I'd imagine you'd still get flagged for even trading it to an alt with a different IP if it ended up with a flagged reseller and they cared enough to ban you.
Detecting the bots in real-time would also be very expensive, and would need to scale with the number of players. That's likely why bans are at certain time periods unless something else has been flagged