IMHO, the Avalanche cannot let Toews walk, for nothing. I don't think the Avalanche can afford to fit the raise Toews will get under the salary cap. So, quandary.
I say trade Toews at the 2024 TDL, window open or not. Maybe for a couple of roster players, like someone opined above, and a 1st round pick (just spitballing!). Then after the TDL run with:
1st pair - Byram/Makar
2nd pair - Girard/Manson
3rd pair - LHD in trade for Toews/Malinski or Foote
Injuries will surely occur and I have zero answers for your "what if" speculations