Starting YouTube, what’s the royalty free music situation like?

Hey everyone, so I am finally starting YouTube and I will be doing let’s plays on video games. I would like to use music in certain portions of my videos, but I’m not sure what the situation is with that.

I’ve done a little bit of research and I’ve seen the top places to go are epidemic sound and uppbeat. The thing is, I’m not sure which one to go to. I’ve seen some good things about both and I’ve also seen some pretty concerning things.

I don’t want to run into any problems down the line, or even getting copyright struck for a video. Especially because I hope to make some money off of this at some point.

I’m not really too sure what their policies are since I don’t really understand all of the legal rhetoric they use. So I thought I would come here and see if anyone could enlighten me.

Which one is more consumer friendly? Or which one would you recommend?
What happens if I stop paying? Does that mean all my videos that I have used their music in get copyright struck?
Could somebody just give me a general overview on how this sort of stuff works?