I do not think you read my post.
The concept of buffer is suspect against the sheer range of modern weaponry. Hundreds of miles won’t be of much use. I don’t know what gurus you read. You don’t need to do that. You can do your own research.
MGM140 190 miles
M142 300 miles
StormShadow 340 miles
and of course the basic cruise missiles
Tomahawk 1200 miles+
There are so many cruise missile variants . . . spend some time on the Wiki. (Russian technology in this matter is superior)
Poland is only about 600 miles across. Cruise missiles launched from Germany, west of Poland, can easily reach Russia, and that considers Belarus in between. Poland would not serve well as buffer even if the entire country were disarmed.
Obviously the Russian Oblast of Kaliningrad has a border with Poland, but that is not the center of Russian society. Though useful to note Hawaii is remote from the US and was not even a state, but an attack on Hawaii induced the US to war.
https://www.rbth.com/lifestyle/330666-official-residences-russia-president-vladimir-putin
Most of these appear to be state facilities, like Camp David or Chequers.
I apologize if I mocked you unfairly.
The whole idea of "buffer zones" is ludicrous and insane.
Nobody gets "buffer zones" with their neighbors.
We have no "buffer zones" with Mexico or Canada, and any suggestions that we should are pure nonsense.
Russia doesn't get "buffer zones", what they must do instead is make nice with their neighbors, make peace, be friendly, maybe even join the EU, maybe even join NATO -- we forget now, that's where Russia was headed in the 1990s, before Vlad the Invader became its ruler.
"Buffer zones" built by military conquest are an insane relic of the past, and Russians need to get over that idea.
If they don't, then "Russkiy Mir" will be a very unhappy place forever.