Yes and no. Putin could rationally expect no direct western intervention or even the level of support we have given. We did nothing when the Russians invaded Ukraine in 2014, and we did nothing when they invaded Georgia. The threat to invade Ukraine was originally made at least as early as 2008 and we did nothing in the intervening years to deter it.
Taiwan is very different. Xi also knows it is of far created economic importance to the west (and the US in particular) than Ukraine is.
The miscalculation was primarilly political rather than military. They expected the Ukrainians to roll over rather than fight. Possibly they believed their own propaganda (and their experience from the 2014 invasion) and expected a lot of Ukrainian support. The invaders were not even prepared to fight and the planning was lead by the FSB, not the military. https://www.youtube.com/watch?v=o9ym9TDs6Dg
"Yes and no. Putin could rationally expect no direct western intervention or even the level of support we have given. We did nothing when the Russians invaded Ukraine in 2014, and we did nothing when they invaded Georgia."
This still sounds like a huge gamble with very high stakes. Ukraine received a lot of Western weapons between 2014-2022, and it was those weapons like Javelin that helped stop the original Russian armored onslaught.
International politics does not reliably work on the principle "actor X hasn't done Y before, so actor X won't do Y now". There may be thresholds that, once reached, change the entire situation.
To look at a historical example, the Allies did nothing when Hitler re-occupied the Ruhr, they did nothing when he annexed Austria, they allowed him to take Sudetenland and later they did nothing when he annexed the rest of Bohemia and Moravia. But with Poland, the threshold was crossed once and for all.
Taiwan is very different. Xi also knows it is of far created economic importance to the west (and the US in particular) than Ukraine is.
The miscalculation was primarilly political rather than military. They expected the Ukrainians to roll over rather than fight. Possibly they believed their own propaganda (and their experience from the 2014 invasion) and expected a lot of Ukrainian support. The invaders were not even prepared to fight and the planning was lead by the FSB, not the military. https://www.youtube.com/watch?v=o9ym9TDs6Dg