>>507320530 (OP)because most of the frontline is highly entrenched. It makes more sense to do a slow and steady offensive around the weakest areas to minimize equipment loses.
Blitzkrieg in and of itself is retarded anyways it's why the nazis largely abandoned it after 1942, it simply causes too much damage to your units because they don't have time to recover and leaves you vulnerable to encirclements. Ukraine tries massive counteroffensives all the time and they all turn to shit cause they burn out quickly from slamming themselves into fortified positions.
Russia will only ever do a blitz if there's a fatass opening like right now in Komar. Currently the layers of fortifications are nearing their end and ukraine can't build them fast enough (or at all really, lack of workers and constant bombing) so a massive offensive will come but it'll take some time so I don't expect it all the way this summer.