The training required to become proficient in Combined Arms Warfare is immense. One cannot climb aboard an M1, Bradley, or Striker turn the key on, and go fight. Combined arms warfare requires the integration of Combat, Combat Support, and Combat Service Support operations. It would take years to make uninitiated soldiers capable of conducting those operations.
I had 4 hours to assemble, equip, and train my soldiers (all Air Defense Artillery) as an Infantry platoon, to include issuing live ammunition before leaving our motor pool.
I took a minimum of two hours in refresher training for my soldiers, whose last infantry experience was back in Basic. Even that was insufficient in my opinion, though we never had an accident, injury, or weapon fired accidentally during the six episodes I was involved with.
I can’t imagine turning over these combat vehicles to Ukraine without significant and thorough training.
Which is why the US has started training Ukrainian troops in combined arms warfare.
U.S. Plans Combined Arms Training for Ukrainian Soldiers-Dec 15, 2022
The U.S. has provided both equipment and training to help Ukraine defend its sovereignty against an illegal invasion by Russia that began in February. Now the U.S. will provide Ukrainian soldiers with combined arms and joint maneuver training as well.
https://www.defense.gov/News/News-Stories/Article/Article/3248075/us-plans-combined-arms-training-for-ukrainian-soldiers/
You might look into the massive amounts of Western training that Ukraine has received for years and is currently receiving.