This would be around 1941 after the fall of Greece.
Seriously are you trying to start arguments on this forum? This is how you start arguments.
We've actually discussed this here before several times and the general agreement is that the Soviet military was so messed up in 1941 and would telegraph the attack so badly and then fail so badly on the attack that it would make their defeat easier and give the Germans cassus belli. I think Halder even lamented that the Soviets wouldn't do them (the Germans) the favor of making things easier by attacking first. It be a worse (proportionally speaking) disaster than 2nd Kharkov was. Much worse. It would be a Luftwaffe turkey shoot on a much more concentrated frontage than they had IOTL, while Soviet armor would break down on the way to the battlefield (they did IOTL on their own turf).
However IMO had the decision been made with plenty of time to prepare for the attack on such a day say in April 1941 then the Red Army is not going to be in its 'peacetime' quarters - units are going to be stood up and shortages in Equipment, ammo, men and stores addressed. Reserve formations are going to be moved into the region under the Aegis of wargames and training, swapping of units etc (with the swapped unit not actually leaving etc).
I am not suggesting that they would defeat Germany with such an attack and I am not convinced that they were capable of conducting the 'Deep battle' in 1941 but initially the initiative would remain with the Russians as they could dictate the time and the place of the early battles and concentrate forces accordingly.
If a good enough maskirovka is maintained and surprise is complete then I can see the German Army suffering many reverses early on before they can regroup and counter attack and its possible that the Red army can close up to the Vistula before the Germans bounce back off of the ropes swinging hard.
The problem with the above is that the Soviets lacked enough equipment to supply all their units, even in Zhukov's offensive proposal only about half of Soviet divisions would even be usable on that attack. That already means they are badly outnumbered by the forces they'd be attacking, which was Romania and Germany. They were in the midst of a unit reorganization of all their units, an expansion of forces, recovering from a purge, and adopting modern equipment while phasing out the old. They'd really just not be able to do much besides use a fraction of their forces with all their old equipment, worse than the Germans standard of 1941, and use their inferior logistics (remember the Soviets side of the border was a different rail gauge than the German side and the roads were a lot worse). Plus the Germans had excellent radio intel at the time, plus overflights, as well as agents all over Ukraine, East Poland, the Baltics, and even as deep as Belarus IIRC, which means they'd know for sure what was coming and react accordingly. Effectively the Soviets would have given away their plans and would pull in Italy to help defend Romania, get Hungary and Slovakia as enemies, and probably even have to deal with Finland, while also having a lot of hostile recently occupied minorities sabotaging them and reporting to the Germans.
Maskirovka in 1941 was effectively non-existent compared to even 1943-44, so don't count on that happening. Logistics were so bad and trucks so limited given stocks even in the civilian economy, mitigated by using only half of the army to attack, and within the TOE of mechanized corps that moving around at the point of their choosing is not an option, especially given Luftwaffe superiority in training, equipment, and experience, plus organization, communications, bases, etc. and they are on alter for the invasion. So the Soviets would rapidly lose air support, including in large part due to accidents (IOTL in 1941 over half of Soviet aircraft losses were due to non-combat causes), which leaves the Germans completely able to use their air power to smash up any threatening ground concentrations, plus they can use their landline communication to maintain communication superiority, while the Soviets, badly lacking radios in 1941, couldn't even fall back on their landlines, which they did IOTL. That leaves them pretty much out of command and supply in most situations is a much worse rerun of 2nd Kharkov, but with the Germans being much more concentrated, prepared, fully equipped, on their own turf, etc. while the Soviets are the ones with all the material deficits.
There is a reason that Zhukov's offensive proposal wasn't even given to Stalin IOTL, no one in the Soviet high command thought it was even remotely rational.