League´s & clubs´ management is a key factor when ranking the leagues, their level of play or attractivenes for fans & (better) players. The 2020-21 season was a special one, with pandemic. German DEL performed the worst from top 6 leagues, they started sometimes in December if I am correct, without fans, earlier they refused to play with 20-30% capacity or whatever because it was not good for their business.
SHL was close to "DEL-level", at least they started earlier.
The Czech league (TELH) had some serious issues with pandemic, interrupting a season for a while.
The Swiss NL & Liiga performed better.
Here are total attendance stats for 2020-21 regular season
KHL: 1,38 million fans
Liiga: 295k
NL: 150k
TELH: 41k
SHL: 6k
DEL: 0
Just reminding, the KHL had 680 games while others around 300-400.
It is just another point of view on performing of the leagues.
For comparison, the 2019-20 regular season (NL, SHL, Liiga affected by pandemic /around 10 games/)
KHL: 4,8 million fans
DEL: 2,3 million
SHL: 2,1 million
NL&TELH: 2 million
Liiga: 1,8 million