When I am relatively still (formally sitting or not), I have noticed that my visual awareness gently flickers. It does not seem profound or enlightening in anyway and may well just be a trick of the light or related to normal saccadic eye movement.

Is this related to 'strobing' in any way or not even close?

The strobing effect you describe happens whenever I go deep into meditation especially while on retreat. I've always referred to it as flickering lights. Almost like a candle flame but the color is white and not that bright. Your exact experience may differ somewhat. At first I was concerned, then curious, but now I just ignore it and it eventually fades. There are some theories floating around but I can't definitively say what it is.

This happens to me as well, and I am wondering the same thing. It happens with all of my senses, including the sense of touch in my face, so I wonder if the visual thing is a result of whatever movement I'm feeling in my face, or if it is actually my visual sense itself that is strobing. I feel like I can do this with sounds as well.

Something to consider: is your everyday visual sense being smoothed over somehow? When you sit still and are able to see things from a calmer, more still and observational perspective is it possible you're seeing what's actually happening all the time but is not usually noticeable?

I've had the same thing. It also happens when people take LSD.

Phosphenes / early nimitta. It's a sign of good concentration.

These can become an obstacle if you actively seek them out.

Impermanence of all experiences. I have that in the visual field, auditory field and in tactile sensations, and probably in the rest of my senses as well if I investigate it closer.

Although sometimes I have noticed that it’s actually just my eyelids fluttering, haha, so some critical investigation may also be called for. Not every flickering shows what consciousness is really like. But some do.

It doesn’t sound like a nimitta to me. I wouldn’t jump to that conclusion until it were at least somewhat centered and solidified.