Poland would kick Russia's ass even without US help lmao. They are nothing like the Ukraine. They are well trained, well equipped, well led, and have a far larger reserve force than Ukraine. In fact, Poland could kick Germany's ass as well and it would be like a reverse WW2.
Oh no...
Sorry to burst your bubble here but I think you need to take a look at for example the polish PT-91 a modernisation of the T-72M1 and then compare it to say for example the comparable Russian modernisation with the T-90M, this is not even comparing with the even more modern T-14 with its unmanned turret. You will find that this essentially repeats itself across all comparable weapon systems from the FB Beryl to the F-16C's Russia has multiple options that are either one or two generations ahead.
Russia has invested heavily in there military and have been showing results, especially in Armored Vehicle, small arms and Aircraft, they have some of the most modern technology available in all areas, while most countries are still using upgraded equipment that are over 3 decades old at their heart.
Do not underestimate how much of a diffrence a technological advantage can bring to the Battlefield especially when not restricted with things like morality towards potential civilian casualties caught in the crossfire.
To help give a visual indicator of what I mean here is an example of the two programs to upgrade the T-72 MBT
Polish PT-91
Russian T-90M
There is literally generational leaps in terms of technology in what the packages include.