Leupold Deltapoint Pro.
No connection to the seller but It’s a solid option for a pistol. I’ve got one on a work gun and keep considering buying this one for myself.
https://www.eotechinc.com/eflx-mini-reflex-sight-mrs
adjustable gas block is up to you but I’d recommend it. You can turn the gas down and tune it to just enough to cycle.
Are you looking at keeping the iron sights or going to an optic? If optic you probably want to get a different upper receiver.