There is also this RAND report from 2019. I will put some quotes here:
"From a U.S. policy standpoint, Belarus’ unrest might present an opportunity to extend Russia by aiding the opposition, removing a long-standing Russian-allied dictator, and supporting liberalization. This aid to Lukashenko’s opposition could come in a variety of forms, ranging from public declarations of support by U.S. leaders to more direct financial and organizational assistance helping the opposition parties reach the end state of being a free and democratic Belarus.
...
In a zero-sum world, denying Russia its one and only true ally would be a clear geopolitical and ideological gain for the West. It would bring an end to “Europe’s last dictatorship,” a long-standing U.S. policy goal. Moreover, it would undermine Russia’s attempt to create an EEEU in competition with the EU, complicate any Russian attempt to employ military force against the Baltic States, and further isolate Kaliningrad."
"
Russia’s commitment in Eastern Ukraine is its greatest point of external vulnerability; local opposition is active and Ukraine is a larger and more capable adversary than any of the other states where Russian troops are committed.
...
Any increase in U.S. military arms and advice to Ukraine would need to be carefully calibrated to increase the costs to Russia of sustaining its existing commitment without provoking a much wider and even more violent conflict.
...
Finally, any geopolitical moves to extend Russia would also need to consider other options that (for reasons of length and resources) were
not considered here in depth—namely, intensifying NATO’s cooperation with Sweden and Finland, pressuring Russia’s claims in the Arctic,
and checking its influence in the Arctic.
...
The successful 2013–2014 Euromaidan protests in Ukraine that led to the fall of the Yanukovich government touched off a dramatic Russian response for many reasons, but among these was the concern that these protests could provide a demonstration effect for anti-regime protests in Russia.
...
Expanding U.S. assistance to Ukraine, including lethal military assistance, would likely increase the costs to Russia, in both blood and treasure, of holding the Donbass region. More Russian aid to the separatists and an additional Russian troop presence would likely be required, leading to larger expenditures, equipment losses, and Russian casualties. The latter could become quite controversial at home, as it did when the Soviets invaded Afghanistan.
...
Alternatively, Russia might counter-escalate, committing more troops and pushing them deeper into Ukraine. Russia might even pre-
empt U.S. action, escalating before any additional U.S. aid arrives. Such escalation might extend Russia; Eastern Ukraine is already a drain. Taking more of Ukraine might only increase the burden, albeit at the expense of the Ukrainian people. However, such a move might also come at a significant cost to Ukraine and to U.S. prestige and credibility. This could produce disproportionately large Ukrainian casualties, territorial losses, and refugee flows. It might even lead Ukraine into a disadvantageous peace."
Read and be enlightened. I read it back when it came out and I thought it was sheer lunacy. But every single thing they say in the frickin report has been happening since. This is clearly the US's playbook for this confrontation with Russia.