I disagree in that (i) Putin will have been rewarded by Trump for this invasion, (ii) there is a significant chance that he will feel emboldened by Trump's public declaration that the US will do nothing if Europe is attacked, (iii) such aggression directly threatens Europe and in my view the UK and (iv) the combined armies of Germany, France, the UK, and Poland (not to mention the rest of NATO other than the US) would be able to crush and drive out Russia from Ukranian territory in a matter of weeks.
So I think that there is a chance that you are wrong in that Europe may determine that it faces an existential crisis and act accordingly just like Israel does in the middle east when facing such threats except that the combined European armies are much more powerful.
So something along the lines of such European alliance forcing Russia out and restoring Ukraine's borders and establishing a DMZ along the border akin to North/South Korea. In my view they possibly seize/blockage Kaliningrad as an unacceptable security risk behind the line. Russia would then have to decide if nuclear escalation is worth it. I think it is improbable given how much Putin and his oligarchs love money and the good life.