Smart move. I adjusted my Privacy and Safety settings so that chat requests on X/Twitter can only come from Verified Users, and that reduced much of the spam.
Scammers tend to target suckers.......and if you register a .us domain name, you're probably considered more likely to be a sucker than those who register .com domains. ;)
I believe that in Australia, that's the standard approach for selling homes (via auction).
https://www.cbc.ca/news/business/here-s-how-to-buy-a-home-in-australia-should-canada-follow-its-lead-1.3826727
I've not used DomainEasy.com, but on their website they state:
DomainEasy - Build and grow your domain business
"Similarly, if you are a seller, We will purchase the domain name from you and sell it directly to the buyer. No transactions whether they be purchases or leases are conducted...
It looks like they've had one for nearly a decade:
Dynadot Opens New Office In Toronto, Canada to Meet The Needs of Growing International Customer Base
Bid suppression is when a competitor agrees not to bid or to withdraw a bid to make it easier for a specific bidder to win
Both parties would be guilty, in my opinion.
Since many of the auctions are operated by US entities, here's what the US authorities have to say:
Bid Rigging
https://www.justice.gov/d9/pages/attachments/2016/01/05/211578.pdf
That's not correct. In your example, their agreement to collude is still bid rigging. Here's a Canadian link:
Preventing bid-rigging: Tips for tendering authorities
Your example would fall under one of the last three types, depending on the specific details.