I did not find anything like this in the rules, and since steamtrades is a part of steamgifts, i thought it's fine as long there is nothing against it in the rules. I checked them before posting it.

https://www.steamgifts.com/about/guidelines I checked the rules here.
There is no such rule in the giveaway section but in the content section, maybe rule 13

"Trading. This site is not for trading, so do not attempt to directly trade games or other items with users in our community. If you attempt to indirectly trade or express a willingness to trade with an unusually high frequency, it will also be viewed as trading."

So it looks like it's no problem to post it 1 or 2 times if you do 20.000 giveaways. At least the rules say so. But I will ask the support, to be safe

Thanks for the info