This really isn't all that much if you pause to consider it. For example. Lets take the larger possible number of 7500 plus 2,300 plus the 4,550 satellites noted up to 2021. That's a total of just under 15,000 satellites. Most of those are fairly small objects, at the most about the size of a typical mini-van, with most being quite a bit smaller than that.
Now, all of this is spread over a three-dimensional topography that's much larger than the total surface area of the Earth, and because their orbits are, as mentioned, three-dimensionally occupying various altitudes, the size of the total topography they move through is enormously larger than just one single surface area in square kilometers of a single hypothetical sphere X km above the Earth's surface. In the least case, even if all existing orbital satellites were stationed at the lowest possible orbital altitude, that's still quite a bit bigger than the 509 600 000 square km of the Earth's total surface. (too lazy to calculate the specific increment in this moment)
Across all of that, just 15,000 objects that are individually smaller than your average family sedan.
For comparison, the island of Manhattan has approximately 116,000 buildings crammed into it. If you spread those more or less equi-distantly from each other across the whole of the Earth's surface, water or air, there'd still be a tremendous amount of empty space between them. That's nearly 10 times as many objects individually much larger than any human satellite, across a much smaller surface area than what's occupied by our orbital satellites.
(Yes, I know we also have a shit-load of other inert junk zipping around up there at tens of thousands of KM per hour, but even if that stuff, most of which is very tiny, were included, we're still talking about an enormous amount of empty space between objects)
To those downvoting a completely innocuous comment like this and my other replies below, which simply put forth a thought experiment for the sake of debate, without asserting anything at all controversial: Grow an adult brain, no? idiotic as the downvote feature is in general, one would at least assume that the self-professed "intellectually above-average" readers of a site like this would use it better than 12-year-old rage-lords on a 4chan thread.
But apart from all the other stuff you mention, you’re missing an important point: these things move. And unless all objects are synchronized (which they are not) they occupy a whole orbit, not only their actual volume. If two orbits intersect, the objects occupying those will eventually collide.
Therefore, they occupy much more volume.