Where’s KiddX when you need him?
OP, the sky’s the limit on ARs. Best to talk to someone knowledgeable and open minded about what you want to do with it. ARs for CQB will be set up differently than ARs for DMR or precision.
For your first one, stay away from NEA. Even though their products are suppose to be better now, their reputation still dogs them.
Go with S&W, Stag Arms, Colt USA, Wyndham Weaponry, Rainier Arms, Daniel Defense, and Colt Canada.
And any AR with a case deflector will be fine for a lefty. Get a Raptor charging handle also. You won’t regret it!