I don't think he is easy to trade or get value for at 6.5M. The problem is that any team who can fit that in probably is not a team he would waive for. My assumption is that he would only waive for the typical meme low-tax contender teams like Florida, Tampa, Vegas, and Dallas - as well as possibly Ottawa or Montreal due to Ottawa still being the adopted hometown of his family.
He will be 35 years old next season and has an extensive injury history. I think that teams are going to be reticent about the remaining term.
Using Vegas, I could see something like Karlsson with steep retention for Whitecloud, a 2nd, and the 3rd or 4th best prospect in the system of Vegas. I don't think they are going to get the return people expect, and I think they will have to both retain and take back questionable contracts with term.
If a contract termination like Saad, with assets going to Pittsburgh baked in could be worked out and legal in the CBA - I think that's how all sides get what they want. Karlsson is still only 34 years old, so that would allow him to sign a lower AAV but longer term contract with the idea that he will inevitable LTIRetire because it's fairly unrealistic to expect Karlsson to still be playing at 38 or 39 years old. Call it a terminate-and-trade.
Because he isn't 35, if his contract was terminated now, they would have more creativity with the kind of cap (won't use the C word here) gymnastics they could do.