The possibility of there really being interstellar UAPs and detecting them

A new article from Scientific American about the possibility of there being real interstellar probes or vehicles here on Earth, that potentially could be detected, and that they might presently be called UAPs. The article avoids even mentioning the other important issues regarding UAPs, such as their sometimes really weird properties and capabilities.

From https://www.scientificamerican.com/artic...planation/ :

The year is 1950. Physicist Enrico Fermi is eating lunch with a few colleagues outside Los Alamos National Laboratory in New Mexico. His shirt ripples in a hot desert wind.  He looks up at the sky and reportedly says, “Where is everybody?” He is talking about space aliens. Known as the Fermi paradox, the question still hasn’t been answered.
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While technological life is probably exceedingly rare compared with bacterial life, if it arose on even one planet billions of years ago, that early start would offer ample time to develop interstellar probes before humanity appeared. If these probes could self-replicate using local materials to create and launch more probes, they could spread exponentially. Recent simulations indicate that even if such probes were limited to Voyager speeds, they could saturate most of our galaxy within a fraction of its lifespan.

So where are they?

(Note: enter the existence of observed UAPs: )
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Have we been too hasty to dismiss the possibility of interstellar spacecraft nearby? Are there limits to our sampling depth that we are not fully aware of?

To help find out, in 2022 NASA commissioned an independent study to determine whether current satellites and surveillance systems have sufficient sampling depth to detect “unidentified anomalous phenomena,” or UAPs (government talk for what could be alien spaceships). The researchers’ conclusions:
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Commercial satellite constellations provide imagery at sub- to several-meter spatial resolution, which is well-matched to the typical spatial scales of known UAP.... The limitation on this data is that at any given time most of the Earth’s surface is not covered by commercial satellites at high resolution—for a particular UAP event, we will need to be fortunate to obtain high-resolution observations from space.

(Note: Intelligence community surveillance satellites have large aperature telescopes with amazingly better resolution, but a correspondingly very narrow field of view and can cover only a tiny fraction of the Earth's surface.)
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(So), we can imagine going back to 1950 and rephrasing Fermi’s famed lunchtime question. His shirt ripples in a hot desert wind. He looks up at the sky. “Where are all the loud, obvious indicators of aliens?” he asks.

When phrased like this, the simplest explanation stands out like a sore thumb. Perhaps aliens don’t leave loud, obvious indicators. Perhaps their vehicles are nearby, and perhaps no one has bothered to check properly—yet.

I don't fully understand the argument.

So they aren't detectable save for when they are detected by radar?

 Isn't that too convenient?

I don't fully understand the argument.

So they aren't detectable save for when they are detected by radar?

 Isn't that too convenient?

I guess the article writer really hasn't thought the problem through. He assumes that legitimate UAPs must be physical UFO vehicles from elsewhere in this universe, perhaps interstellar robots that got here thousands to millions of years ago after vast journeys at sublight speeds. This would be at least remotely plausible according to our current science. Then he points out that there is no apparent reason they would shout out their existence in a way that would be easily detectable, in particular by satellite photography. Leading to the conclusion that they might actually have been here all along but mostly unobserved except for very occasional accidental encounters with radar and electromagnetic interference of various kinds and brief accidental video and photographic recordings. And then therefore the conclusion that the "Fermi paradox" was misstated. He doesn't consider any of the weirdnesses associated with some UFO encounters, including abductions; he doesn't consider that his reasoning may be valid only applied to a subclass of UAPs - UAPs that are physical alien flight vehicles, as opposed to other types of UAPs that may be semiphysical "ultra terrestrials" from another parallel Universe or dimension, or time travellers, or psychic manifestations of the collective unconscious, or varous other far-out hypotheses.