Tv has a minor impact on merch. But i repeat minor.
It indeed has a positive effect on season ticket holders. I can tell you that it does not guarantee that you will have an increase despite having a weak season
But the true benefit is felt if you have an arena larger than league averages
If you have a small arena, rank around the upper echalon of the division in terms of revenue, then tv will not help as much.
I earned 370k per game.in div 2. And before tv i had difficulties passing 340k.
A good recommandation, and i will partially agree with what the other person said earlier, level is a safe bet in terms of benefits.
Ultimately I recommend building arena to the level of the division you are promoting to and plan on staying. And only later consider building infrastructure.
The lwague averages are available on the community pages, starting as of last season.