Yes exactly, our Milky Way blocks a lot of the view. Plus most of them are irregular and small (compared to our Milky Way at least) and then it's easy for things to "get lost"

nope... a similar smorgasbord of large and small. However, the Virgo cluster does have several elliptical galaxies which "we" do not have. We have two large spiral galaxies and a bunch of irregular ones, but no elliptical.

No, that has nothing to do with that. We're talking WAY different scales here.

For life to develop you do need some stability of course, I mean, a supernova going off next door won't be helpful. :-) But for life we're talking about the local environment. Things like: how far is the nearest star? What is the chance of trouble nearby?

As for a crowded set of Galaxies, the chance of galaxy collisions is indeed higher, but when galaxies collide, in general, stars do not collide. You do get a BUNCH of new star formation, but locally things can still be stable. Looking at individual galaxies within the Virgo cluster we're not seeing much different structures like what we see in our own Milky Way...

Our "cluster" is called the "local group" and contains about 30-35 galaxies. The two largest are our own Milky Way and the Andromeda Galaxy. The radius of the local group is ~5 million lightyears.

For comparison, the Virgo Cluster is relatively close by at 60 million lightyears and is a bit larger in radius: 7.5 million lightyears *but* contains between 1300 and 2000 galaxies.

So, using that comparison, as well as most other local clusters, our local group is indeed quite sparse.

No real answers, but some thoughts...
Metal in the atmosphere is normal of course, because a lot (most) meteors that are burning up in the atmosphere are metallic. From this newspaper article it is estimated that about a ton falls to Earth every day. Using another "source" this page from Smithsonian magazine estimates it to be about 50 tons.

Either way, we're talking about a significant increase. But would there be an effect, and what would is be?

Obviously, the amount of dust that is swept up from the Earth by wind is higher by several orders of magnitude, but won't reach that high an altitude.

Potentially more important though... the question is about metal in the atmosphere, but what percentage of said satellites are actually metal? OP makes the implication of 100%, obviously this will be way lower (10%?), but if true, what constitutes the other 90% and what are the implication of that? A nice piece of iron burning up in the atmosphere after all, is not the same as some Lithium Ion battery encased in plastics...

actually... its a dance of life :-)

If you look at the above image you see a blue hue, and even some bright blue areas: that is all star formation of new hot blue (O& B) type stars... billions of them. And that all occurs because of the collision.

Here is a link to a high res of this image:https://stsci-opo.org/STScI-01EVVF7ZHXFXBVGZXNRN3F3Q2S.jpg

Yup. Collision or a close flyby. For galaxies this is relatively common. Our own Milky Way

will experience something similar with the Andromeda Galaxy, because we're on a collision course.

But no worry, in general galaxies collide, but individual stars do not. Plus it's still a bit of a wait.

Plus 6 weeks vacation pay...