Pretty sure this guy’s wrong. In another comment he refutes something that actually happens. Transfer fees exist and they are utilized to bring first round picked European prospects over — prospects like Leo Carlson. He says it doesn’t, he’s clearly wrong. He doesn’t know the rules.
This guy and Slava Malamud are not reliable or neutral interlocutors.
I certainly don't know all the specific details on a league by league basis but the difference is the NHL has explicit transfer agreements with other European pro leagues and the CHL that are part of the CBA. Leo Carlsson was just a standard transfer fee paid based on the NHL's agreement with the Swedish hockey association, NHL teams can't otherwise individually negotiate or pay transfer fees outside the CBA.
It's not something the teams negotiate for each player either, there's just a set number based on factors like draft position and signing date outlined in their agreements with the individual European leagues and/or national hockey associations. It's all a defined above board process for the other leagues, while the NHL and KHL haven't had any formal relations after the NHL cancelled their MOU in 2022 and there was no transfer agreement with the KHL pre-2022 either.
There is speculation that the rules may have recently changed with the KHL splitting from the Russian hockey federation and that the Flyers may have paid to break Michkov's contract. I have no idea if that's true or not, but if it is now possible for NHL clubs to pay transfer fees to break KHL contracts that's a very recent change.