They need to look for ways to take the fight to Putin and cripple his ability to keep going.

Why? That's almost never necessary when implementing this kind of strategy. The Muhajedin didn't attack targets in Russia, the Vietnamese didn't attack targets in the U.S. It's often sufficient just to attack the invading forces in-country, where you can still inflict all kinds of casualties and loss of materiel and drive up the expense of prosecuting the war - and you don't have to extend yourself too far to do it.

Early on you guys kept bringing up "asymmetry" and related concepts but then later noted that we "haven't reached that phase yet". There's a vast difference between having to control an entire country by garrisoning troops there and run it on the daily and a slow moving front line fight.

Yes - the difference is that you typically suffer smaller costs and casualties in the phase after you've beaten their army than in the phase where you have failed to beat their army and have to keep fighting them on the front lines. The country being invaded is in a better position if their army hasn't been defeated. They can (and often do) have the ability to inflict pain and costs on the invading country after their army's been crushed - but they have more ability to do that before their army is beaten. Which is why Russia's in such terrible financial shape because of the war.

"Insurgency" is a later phase in these kinds of asymmetric struggles - and Russia would love to be able to get to that phase instead of the one they're in now, which is "still getting pounded by a well-supplied regular army."