I think your theory has more than a bit of merit.

I see this post is two months old. I've seen that there are even maps of a DMZ running near the current (Jan 2023) front lines, but I don't know how old they are.

The Russians continue to build up forces for a winter offensive, while slowly degrading Ukrainian infrastructure needed by the Ukrainians for military logistics.

There has been another "Popasna" like breakthrough by the Russians in the east at Soledar, but it is far too soon to know if Russia will be able to capture surrounding territory as they did after Popasna.

In any case, the new Russian troops are not simple conscripts, and Russia has huge advantages in both men and equipment compared to Ukraine.

The question going forward is how much NATO is willing to escalate to keep Ukraine from losing. So far each escalation has lead to short-term losses by Russia, followed by aclimation to the new weapons, followed by a resumption of slow grinding progress in the East. Barring NATO troops entering, Ukraine will continue to slowly lose.

NATO troops directly entering the conflict will bring unknown levels of political problems in the EU. The public is NOT in favor of escalation, even at a weapons level. EU troops fighting Russia directly will (IMO) lead to more high-level resignations like Germany's defense minister a few days ago.