Look at lasers for low light. A friend who is an old SEAL buddy is still a contractor with recent combat time. He swears by green lasers. In all but total dark, in urban and “suburban” areas, if you can see a bad guy, you can hit him with a regular visible green laser out to 300 yards. He has access to NVGs and IR lasers but prefers eyes-open with a green laser for getting the hit. You press it on with a remote pressure switch just before shooting, then it’s back off. He swears this works best for him, and he could use any gear he wanted. And this is something any civilian can buy.
One of the best defense rifles I ever owned was an HK 91. The trigger pull sucked but I got used to it. I never used anything but the diopter sight that it came with. Good hits out to 400 meters. I sold it some time back and have been kicking my ass on that decision ever since.