I think you’re drastically underestimating the technological leaps that would be required for some of the things that these objects have been observed doing. I’d recommend you take a look at this paper, it goes over a couple highly credible sightings and calculates estimated accelerations for the sighted objects, as well as estimations of how much energy would be required to accomplish that acceleration.

https://www.mdpi.com/1099-4300/21/10/939/htm

Spoiler: In the most credible case in this paper, and arguably one of the most credible UFO sightings to have ever been recorded, the USS Nimitz sighting, the objects sighted (visually, on radar, and on both IR and visual light videos) were seen to accelerate at speeds of over 5000g, which would require energy output around 1100 Gigawatts. Which is around the total capacity of every power plant in the US, circa 2012. Producing that amount of energy in an object roughly the size of an F-16 and using it to accelerate something so quickly that hopping between solar systems would take 1.2 days from the craft’s temporal perspective is so far beyond any technology that any military has produced as to be practically magical. I do not exaggerate when I say that any country that had the technological capability to do shit like that could effortlessly conquer the entire planet within a week if they so desired, it is the ultimate strategic trump card, it breaks MAD in half. In my opinion, there is no way in hell any military has this technology and yet simultaneously continues to develop utterly inferior conventional aircraft, it just doesn’t make any sense.