I often hear Rites of Spring mentioned as one of the earliest examples of emo. They’re quite good. There are some decent videos and articles out there about this topic, and while most of the 80s and 90s bands mentioned don’t sound anything like 2000s music, there are a lot of things that you can hear and it’s cool to see all the little elements get experimented with. Definitely do recommend going down a rabbit hole. I am sure there are some pretty good playlists out there.