For anyone interested in Star Wars: The Bad Batch, here are the Clone Wars episodes I think would be the best primer, in chronological order:
Clone Cadets (s3e01)
Rookies (s1e05)
The Deserter (s2e10)
ARC Troopers (s3e02)
The Citadel (s3e18)
Counter Attack (s3e19)
Citadel Rescue (s3e20)
Missing in Action (s5e12)
The Unknown (s6e01)
Conspiracy (s6e02)
Fugitive (s6e03)
Orders (s6e04)
The Bad Batch (s7e01)
A Distant Echo (s7e02)
On the Wings of Keeradaks (s7e03)
Unfinished Business (s7e04)