I'm kind of curious as to how this would have played out and/or his full intentions - I don't think Putin set out with a conquest of Europe in mind but I'm certain that if he'd simply rolled over Ukraine, gained their man power pool, all the production facilities such as in Kharkiv, etc. and the West just whimpered he'd have continued until stopped by force assuming the West would more likely iteratively sue for peace than confront him.
If he'd taken Ukraine more or less to plan without huge losses, despite some Western support, IMO he'd have turned to places like Moldova next, and building up forces against the Hungarian border with a join us or die kind of threat to bring them into the fold in a similar manner as Belarus is to Russia, eventually turning to the Baltics and possibly trying to replay 2014 to slowly carve off Poland.
EDIT: For clarity these are 2 different scenarios with the first Russia taking a more direct approach against Europe to see how far they could push it.