For massive rating differences like that, I used to try and avoid them whenever possible, but then I realized something. Lots of players are much higher in one time control than another, but they can still be really bad at that other time control.
It's possible someone could be 1200 rapid with more time to think, but 500 blitz because they play much worse when rushed. In fact, lots of these players mean that you can outplay them in time pressure because they have less experience there!
The chess.com pairing system is really good. I've also encountered players much higher rated and then after the game realize they were on a tilting session and losing streak... which also makes it more likely for me to win. All of these factors are in your favor. Just play the games and focus less about your opponent and their rating and more on your game. GothamChess and many others even play better when they DON'T know their opponent's rating:
I was playing blitz ( I'm 530,highest elo is 630) and I got paired up with a guy in 1235 in rapid