Then you must have not been paying attention.
A summary of those failed predictions: https://www.rferl.org/a/russia-ukraine-invasion-predictions-...
It's a roughly equal part of underestimating Ukrainians and overestimating Russians.
> Those that did make any prediction about the length of the war pointed towards modern wars like those in the middle east, which demonstrated that modern wars do not end suddenly regardless of what progress either side makes.
You mean like Crimea where the resistance never died down and was an active battlefield with daily activity of partisan groups? /s