Everyone with any military training has been laughing at how bad Russia was using their tanks, thus allowing them to be destroyed. Losing some tanks in battle is a given, but it is generally believed that if Russia was using tanks according to the Soviet doctrine they knew well they would not have lost near as many - as proof of that Thesis, Ukraine has been using the Soviet doctrine and not lost nearly as many tanks. (Ukraine lacks enough artillery to apply the Soviet doctrine of war which is why they are using drones - they have now developed new styles of fighting that uses the drones they have, but tanks are still an important part of war)
Tanks are the heavy cavalry of the modern era, their main use is to break defensive lines.
Or rather, was. Neither the Russians nor the Ukrainians, operating diverse tanks on the bases of different doctrines, managed to do much breaking with them. The battlefield of today is just too different and much more hostile to anything that moves in the open and is big and slow enough to get hit.
