>Do yiu think I need a left handed AR?<
No. In fact, even a left hand setup for the safety is of minimum advantage. You do need an AR with the ejection deflector if you don't like hot casings down your shirt. There are models that don't have those.
Get 1000 rds .22 LR ammo, go out and shoot the hell out of it, bench, offhand freehand, with a tree rest, fast shooting, slow shooting, paper targets, plates whatever.
Get a few hundred rds of 223 and do the same - you'll see.
Any scopes you use, you'll probably need to reset focus, and re-zero before you get into your re-training.