The latest setback for the NHL was the 2020-22 COVID pandemic.
It had a high impact on the league's bottom line and prevented the NHL from raising its salary cap to a proper number which has been reduced to $1,000,000 per year. It has handcuffed teams to be in cap compliance and has managed other teams to broker deals and bankroll salaries to make trades work.
It's expected the NHL will resume its involvement with the Olympics as many players from NHL organizations will play in this tournament. This practice has been barred for many years, but the appetite to return is there.