The heavy western tanks are used to pick targets off at long range 1.5km - 2.5km prior to trench assaults. The targets are spotted by drone operators. Very effective they are too.
The French light tanks are used as mobile artilary Though there role will change if a breakthrough occurs.
The critical part of the Ukrainian strategy is effective counter battery fire and spotting and taking out artilary. Conventional artilary is the only advantage that the Russians has and it is now being rapidly eroded. HIMARS+M270 is now being used closer to the front line lines to take out artilary and local supply logistics. JDAM and Storm Shadow are now being used to take out longer range targets.