https://en.wikipedia.org/wiki/Sting_(drone)

The distance to the horizon at sea level, is 5km, a high flying drone only increases that.

With a 25k range and a 10k ceiling, and a stupid low unit cost it is dead easy to deploy this en mass to protect vital infrastructure and deny lower visibility routes (valleys, places where detection range is short).

They (Ukraine) are heavy users of YOLO (image model) that runs on some very low end hardware (sub .35 watt for the most efficient models) - and have shown it to be effective for terminal guidance.

The US has a budget item for 2027, DAWG (defense autonomous war group) - that requested 54 billion dollars. This is larger than the USMC's entire budget. This is a quite admission (another one) that the US is far behind, and the things that are going on in the Ukraine are, terrifying.