I have approximately zero confidence that if I see an error message that says "our support team received the error" that anyone has received the error.
In fact I would generally bet thousands of dollars against that.
That depends. There are common errors where the support team gets that information because they have seen it before and having seen that error changes the support script in a hopefully helpful way.
Companies generally have massive amounts of errors though. They investigate the most common errors for their script. Sometimes when someone figures out a different error they adjust the script. Most errors though never get investigated.
The only place I've worked that logged out technical details (inside of a <details> element) was also the one that did the best with logging those in Bugsnag and then having engineers triage them and create tickets. I think those things are very connected.
I very much believe this gets dumped in some kind of ELK stack or something like that. And quite often teams will monitor to ensure that some new error message isn't going wild and alerts are sent out.
Single errors mean nothing, unless of course you're putting in a support call and we're directly looking it up.
Companies generally have massive amounts of errors though. They investigate the most common errors for their script. Sometimes when someone figures out a different error they adjust the script. Most errors though never get investigated.