If they do a few trades then this is what I would do
Becky Lynch swap with Bayley.
Becky goes over to Raw, she wants Ronda but Alexa Bliss says she has to win the Rumble, she wins the Rumble or they do a thing where Becky and Nia eliminate each other at the same time, they have a match at Elimination Chamber with the winner facing Rousey at Mania.
Bayley gets a fresh start on Smackdown, she has barely had a feud with Charlotte, Asaka etc, would be good for her career.
Next trade will be AJ Styles swapping with Seth Rollins
Each guy needs fresh opponents, would give them a fresh start, both should turn heel really as they are a bit stale as babyfaces.
Tag team trade, I would trade The Usos for The Revival to give some newish tag matches for both divisions
I would also swap Baron Corbin for The Miz or maybe Kevin Owens for The Miz.