There's no evidence for the Turkish personnel in Azerbaijan, but I still thought that the Army building part and NATO standards army vs. Soviet is an important factor not to be overlooked.
The biggest factors were redevelopment of Special Forces, which are now the best trained and equipped in the Caucasus, possibly in the region now due to experience, massive number of loitering munitions working jointly with UCAVs, Azerbaijan managed to establish effective battlefield management and integrated Soviet, Turkish and Israeli systems.
for example, Turkish UCAVs would guide laser guided bombs from Su-25s, guide Israeli loitering munitions in areas of heavy SAM presence / out of ammunition.
Turkish UCAVs would also guided Israeli MLRS, such as long range Extra and Turkish laser guided
TRLG-230.
Special Forces led the advancements on the ground, and managed to take Shusha, the most fortified city in Karabakh, on foot, while the adversary had heavy equipment. and they managed to do it in just a few days.