Yesterday I was trying to sell some Rocket League items and a guy sent his “Steam ID” so I could add him. Unfortunately I wasn’t paying full attention and opened the link. The link is obviously fake. But I was wondering if simpily opening the link dangerous. The link is: <Redacted for protection of others>
I didn't input any infomation or download/run any files from the site.
If you have a security suite running on your machine, entered nothing, and nothing odd has happened since then I would just do a few more days of "watchful waiting."
It's likely that there will be no issues, but if things suddenly start seeming unusual you could have an infection.
It can also be useful (though if you don't know what's normal, it's typically not, because many will worry over the perfectly normal) to use something like Glasswire to see if you have network traffic going somewhere unusual. I wouldn't go that far as a first step, though.