Scroll buffer super slow and limited

There are a lot of posts here with things like "There should be a way to jump to the first message" and "Don't jump to the bottom when you switch channels" and "Improve search", but the biggest problem with scrolling is how painfully slow it is. Scrolling up and down in old chat programs was never an issue, you could browse years worth of conversations in multiple channels, and search through them quickly with keywords, jumping to the point in the conversation. I get that things are a little different now, things being completely server side, but it's just text. How hard would it be to send maybe 2MB of text to the desktop client when someone starts scrolling up? More importantly, the text shouldn't be unloaded as it goes off the screen, scrolling down to what was on your screen seconds ago shouldn't take time. In all of computer history up until recently, the ability to quickly scroll up and down without waiting forever was a given. If there's some technology limitation that makes scrolling through text in modern day impossible, I'd very much like to hear the details from a developer. In Discord's defense, Microsoft Teams has the same issue, only much worse.