If someone were to record a flawless, 4K video of an actual alien walking around or a spaceship flying overhead, people would just think it's a deep fake.
Lets put it this way: in the 60s, a photo was not a simple or common thing. Only a few people had a camera at hand, and films could only take 20 to 30 pictures, so they were used sparingly. Still, many UFO pictures date from back then.
Nowadays, everyone has a camera on person, and you can do thousands of pictures in a row. There are millions of recording video surveillance cameras everywhere. So if UFOs exist, there should be myriads of pictures and recordings, many of which in top notch quality, where you could read the labels on the little green mens console buttons.
Take a picture of a plane with your cellphone. Not to say that there are aliens in any way, but the devices we have can barely capture a decent picture in a grocery store security system. After 20/30 meters pretty much nothing is clear without specialized equipment.
There is a very reasonable explanation for this: If we are a topic of research for them, they could have simply stopped studying us in the same way
Take our own science for example. We pull out of studies when the funding dries up. Maybe the aliens’ government grant ran out. Or, perhaps they have a policy of avoiding interference with the subjects. They could have changed methodology in response to the threat of high resolution recording equipment
Nahh, any species able to come close to interstellar travel would be able to observe us from afar. We can already take good data on other planets' atmospheres. It's not going to be too much longer (probably still past our lifetimes, but) before we can take spy satellite quality photos of the surface.
Sure, some alien species might prefer to be more hands-on, but I'd hope they'd also recognize the destructive power humans have and stay away; It's a lot easier to break something than to invent it, and few things remain even recognizable after being hit by bigger military weapons. A lot of older movies/media relied on that fact to make the other thing seem so fantastically strong. Like the alien ship shrugging off a nuke in Independence Day.
That may be true, but there's only so much you can collect by remote observation. I really like the "interstellar scientists" take, because it's something I can see us doing. If we obtained warp drive, we would want to understand how other intelligent species develop, and how similar their conditions and course of development is to our own.