How wide is the window of opportunity for Russia

The window of opportunity must exist because there is no other explanation for such assertive actions on Russia’s part. This comment on MoA has some interesting opinions on how wide this window is:

I put in some time researching how far US is away from fielding a hypersonic missile. In 2019 they successfully tested a lab built boost glide missile that functioned correctly and good accuracy. They have now moved into production and crew training and expect to have them deployed and functioning in 2023 with initial prototypes for training through 2022. Two failed tests to date due to production booster not launching from the aircraft. There will be a few teething problems but under current circumstances these will be overcome quickly and will quite likely still be deployed as early as 2023 if not sooner. This is the window in which Russia must get a security agreement with the US.
Reading through the Russian proposals, the overall picture of them is a buffer zone all around both Russian and US in which neither side can place their missiles or militarize. A type of no mans land and, on the Russian side, this must be in place before US deploys hypersonics. If US get to the stage of deploying these missiles before there is a security agreement in place, then I think Russia will strike first, no period of escalation, rather the complete elimination of a threat.

On the American side, going on what is occurring, they may well spend this time trying to create a situation to launch an all out strike on Russia. I see the Russian presidential spokesman has voiced the possibility of the current propaganda indicating a provocation in Ukraine. The Brits have a couple of nuke armed subs and will join the US.
US nuking the Soviets was always a British wet dream and I think would at the moment be quite capable of creating a provocation separate from the US with the aim of inducing the Americans to launch a strike against Russia if it looked as though US was willing to enter a security agreement with Russia.

More details of the US hypersonic program in a further comment:

It is a government research center or lab that has developed and successfully tested the missile in 2019
August 2019 https://www.defensenews.com/digital-show-dailies/smd/2019/08/07/final-hypersonic-missile-contract-awards-im
The technology is owned by the government labs, he noted, “so we are transitioning that out of the labs into the commercial marketplace. That is a really hard thing to do, but there’s a lot of energy and a lot of momentum behind that outcome.”

Other links
https://www.defensenews.com/land/2021/02/09/us-army-begins-equipping-first-unit-with-hypersonic-capability/
https://edition.cnn.com/2021/10/21/politics/us-hypersonic-test-fails/index.html