I first became aware of this group in the early 80’s as I was collecting comic back issues and purchased the Avengers. Korvac saga was great. Starhawk could not see “Michael” in the Queens home. I recall the Avengers & Guardians took a bus. They were all killed.
It was pretty much the same for me. I tracked down back issues of Avengers, had no knowledge of the story, and was blown away by it. I had known about the Guardians from their appearances in Defenders, which were also good.