For "armchair generals" (like myself), this may interest you...
What is the strategy in Ukraine?
I can't go into it all, but I've found very illuminating some of the commentary by geopolitical expert Peter Zeihan...
In this video, he points out something very interesting... Russia started the war at dawn, during light.
Unlike the USA, which often starts wars in the dead of night.
The reason why? Russia doesn't have a good supply of night-vision technology... So they need daylight to operate effectively.
This leaves a possible strategy open - which is (he implies), for the USA to supply Ukrainians with night-vision technology. With that, the Ukrainians could better rule the night, compared to less-well-equipped Russians...
(He talks about this about 9 minutes in...)
Ukraine and Russian Invasion Paths | Peter Zeihan
https://www.youtube.com/watch?v=3LccNVCBmgs
It is highly unlikely the US will send any troops to Ukraine itself.
The reason why is because fighting the Russians directly could start WWIII.
The US is more likely to try to help Ukrainians through equipment supplies, and also sanctions...
(This is originally what happened in Afghanistan when the then Soviet Union invaded Afghanistan in the 1970s. The USA didn't enter, but supplied those fighting the Soviets with military equipment. The Soviets/Russians finally exited in 1989. The USA didn't enter Afghanistan until the Soviets/Russians were long gone, in 2001...)
Best wishes,
Dien