You don't have to get the clips individually, you could download entire games, and not every clip has to be an important moment. You can also throw in relevant images like when you mention champions 2022, you could show images of the location and stuff like that to break up the clips.
There's some sites where you can download a specific part of the video I'm pretty sure, wouldn't know any off the top of my head.
The transitions are really simple (also kind of fun to learn), and if it comes to it. I think you can use one's someone else made and uploaded to use.