#1 Kevin Owens and Keith Lee should switch spots on RAW and SmackDown

This is a trade that would help reshape the main event and upper mid-cards of both RAW and SmackDown. Kevin Owens had multiple shots at Roman Reigns and was defeated every time. He also feuded with Rollins for much of 2020. Owens has also tangled with Sami Zayn, Aleister Black and Apollo Crews (briefly).
Short of forming a tag team with someone to go after tag team gold, Owens needs a big change. He hasn't won any tag team titles in WWE so that could be a good direction. But to refresh his tank and give RAW another potential challenger for Lashley, Owens should be traded to RAW.
Did you know a top WWE Superstar just wrestled outside the company? More details HERE
The All-Mighty will presumably walk out of WrestleMania Backlash with his title. After that, Lashley needs to face someone other than Drew McIntyre or Braun Strowman. With Randy Orton currently in a tag team with Riddle, that takes out one legitimate challenger.
The Fiend seems like the most logical choice to eventually dethrone Lashley. He hasn't appeared since 'Mania and might return after WrestleMania Backlash or closer to Money in the Bank.
Owens would offer up a different challenge as they haven't crossed paths much in WWE. In exchange, Keith Lee should go to SmackDown. While Lee hasn't had the title opportunities on RAW, he would still be a good foil for Lashley. Lee has been out, however, for the last few months with an undisclosed injury. He was reportedly set to win the United States title at Elimination Chamber, but that injury kept him out of action.
Once Lee returns, he will be a perfect challenger for any heel. If traded to SmackDown, he could ease back into things by going after the Intercontinental Championship and Apollo Crews.
If he's back and better than ever, he could eventually challenge Roman Reigns for the Universal Championship. His fiance Mia Yim is reportedly part of the SmackDown roster, so Lee joining the Blue brand would keep them together.
Both Lee and Owens are faces that have the backing of the WWE Universe, making any title match they are in a must-watch bout. Owens needs a new start and Lee joining SmackDown would build on his moment with Reigns from Survivor Series in 2019.