I doubt anyone here can help you decide. But we can add choices and make it more confusing!
Do you mean low or no magnification? None would be a dot of some sort, so an Aimpoint, EOtech, TriPower or ACOG Reflex. Or Holosite (cheaper EO), or some other dot. Or a Docter if you want to go small. Or OEGs! Or..., or..., or... Lots of choices, but they will also break down into categories, of size, reliability, brightness, type of aiming graticule, batteries or not, auto-on or not, etc.
For low magnification, the choice is easier. Maybe ELCAN, but they are tall and bulky for an AR, so really ACOG. I say, ACOG Compact. All have the light-gatherer to allow the Bindon Aiming Concept (probably TM'd by Armson!). They are also... compact. Which is better for the smallish AR, I think. They are pricey, like $700+, but a full-sized ACOG with an NSN will be closer to $1000.
Also, with the war needs, and the sudden army realization that optics are valuable, its hard to find anything good, and there are NO deals on them. Expect to pay full retail for something not /quite/ what you want, and to wait 10 weeks for delivery. I am personally gonna get a holdover, like a lightly used Holotsite, and get an ACOG compact next year sometime. If we haven't invaded anyone else by then.