So I've been trying to stream gta sa for the past few weeks, I cannot get the game to show, on OBS, I kinda need a guide on how to do this, also how to make livesplit appear on the side too, any help would be awesome

Are you using OBS studio or just regular OBS?

If you're using regular OBS, then game capture should work just fine, it always has for me. On OBS studio, the source might take some messing around with to get it to work, involving combinations of OBS studio restarts and game restarts.

As for LiveSplit, I'm not sure if window-capturing it would work with the game in fullscreen with one monitor. If you have two, then put it onto your other monitor. Otherwise you might have to run the game in windowed mode.

Just normal obs, when I use game capture, the game appears but it is in small resolution, and there is a red border surrounding the rest of the screen.

In the game capture properties, try checking "stretch image to screen" and "ignore aspect ratio"