Some people may not know ens is an ERC721 standard NFT and can be traded on NFT market such as opensea.
If an ens name is already registered, I suggest adding a opensea link(the detail page of the ens name on opensea ) in the ens.domains detail page. If he/she want to buy the ens name, he/she could make an offer on opensea conveniently.
That’s a good idea, but I don’t think app.ens.domains will add this link because ENS transactions are not part of the ENS-based capabilities and the team won’t add third-party links to the app. Second, even if you want to add a link to facilitate transactions, you shouldn’t leave Opensea as the only option just because it’s the largest.