On a scale of 1-10, where 1 is grounded in reality, 5 is naive optimism, and 10 is cultish delusion, some writers of this forum rates 40 or 50 in their assessment of contemporary Russia’s ability to successfully engage NATO.
It goes the other way around too, with some people overstimating NATO's political willingness(outside of the UK and US) and ability to provive equipment and training to Ukraine without afecting their own readiness and the fact that NATO, should they be dragged into the conflict themselves, is still mostly geared and trained to do COIN and colonial policing in the Middle East and Africa, not fight a near-peer war, no matter how many Strong Europe excercises they do.
While it is true that Russia has been fucking up badly in many areas thanks in big part due to incompetence, misuse of assets, it is also true they aren't fully commited to this war as they should, which in turns exacerbates the impact of the blunders as they can't pick up the slack somewhere else. A fully mobilized Russia will be something different, and there is no way around that.
This is compouded by the fact that Ukraine, having been part of the same country once, is familiar with Soviet-derived tactics so they kind of know what to expect and where, which is also backed by NATO's ISR assets that act as a force-multiplier. But this also points out to the fact that Ukraine should be doing far more better than they are, and thats against an enemy with numerical inferiority when it comes to infantry and technical inferiority in UAV and ISR assets.
A lot of the discussion make it seems like the Ukrainians are as badly armed, trained and backed as the Houthis or the Talibans, which is far from it. The Houthis can only dream of having the amout of ISR support Ukraine is getting and they still can mount counteroffensives better than Ukraine does.
A full blown NATO-Russia war would change the dynamic of the conflict, but this change also goes both ways; yes, you'll be seeing Leopards 2 in Lviv and whatnot, but now NATO ISR assets can be freely targeted as well, and they aren't that many to begin with, just to use an example.
All of this hinges on the assumption that NATO won't tear itself appart at the seams of self-interest and political expediency of each its members in the process of deciding to jump all in or not.