I posted this right as the last thread locked in response to a statement that we are currently seeing the best Russia has on the field of battle and that no- they aren't holding some supersoldiers in reserve:

This is why I have come round to the idea of a no-fly zone or at the
very least, the safeguarding of escape corridors. Unless Putin is
really willing to use nukes (Which I personally don't think he is.).
An EU or UN lead no-fly is absolutely the way to go. Putin has already
made it extremely clear he doesn't want to face Western troops (I wish I
could find the article stating it but it seems elusive currently).
Honestly, any EU / UN or NATO involvement would end this farce
immediately.