Defence procurement bungles and wins

[ElwoodBlues1]

UAVs operate in tandem with aircraft. If the other side dominates the air, then drones would be picked off pretty quickly. That's the remarkable thing about the Ukraine war: everybody assumed the Russians would quickly dominate the airspace but Ukraine's fighter pilots and missile defence systems have ensured the Russian fighters are occupied with other threats.

Russia havent deployed their best jets/pilots on mass as yet, their commanders dont want to risk them after losing a SU34 early in the conflict to the Ukraine anti-aircraft missile systems which as you described have proven very adequate.
Its the same with their best troops who have been kept back as well, Putin thought his conscripts and armored columns would do the job but they have also failed with the infantry not so keen to engage the Ukranians on the ground and leaving their tanks exposed to very good anti tank weaponry supplied by the British in the main.
Ukraine were hard hit when they split from the USSR and had to give up their nukes and airforce which included a decent air fleet of bombers which would have been very handy today. Lot of their Nukes were in silo's which would have been a major deterrent to Putin as would those bombers which could carry nuclear payloads as well as conventional bombs.