'Changed tactics' - is relative.

One can't punch through a well-fortified frontline, nor take well-fortified strongholds with 'technoguerrilla' tactics.

'Changed tactics' - is relative.

One can't punch through a well-fortified frontline, nor take well-fortified strongholds with 'technoguerrilla' tactics.

One has to deploy heavy equipment to do so.

However, once one is 'through', then it's easy to 'return' to what Ukrainians do the best: 'dancing around the Russians' with their 'technoguerilla' infantry.

Thus, I would say: one was necessary at the start, enabling what's done now.