There is none, this is one of the most asinine discussions on an ongoing basis on these forums.
Make your team more desirable and make players want to come there. Money isn't the only thing. If lack of income tax is the only thing, then every player would be with the Knights, Bolts, Panthers, Kraken, or Predators.
Nothing anyone can do to change that, and the league should not step in. It's not a competitive edge, it's just a fact of life and has been forever. It seems like this is the only sport with fans constantly whining about something totally out of anyone's control.
Your team needs to incentivize why a player should go there to make that up to 15% income tax in the US and higher in Canada not as big of a deal. That's what teams have been doing in pro sports for decades, and same thing with businesses.