Be careful what you wish for. 25% of Norwegian men never father children, and 15% of Norwegian women too.
So in the end men who never father children are being taxed for other men's children. Is that moral?
The easier, ethical way to increase fertility back is to bring morality back to society. If you make sure your kids are raised near other people like you, you cheat the system that the most advantaged people in society have (better looking, better finances etc). Why isn't the character of a person a valuable trait? It's because people who have those traits take it for granted, and those with other traits want character as a trait to be devalued. Imagine if every man would taught their daughter/son/wife to judge people by their character. Taught that loyalty is a virtue.
And then only let their children hang out with people who also value those with character.
Current society is bad for men and women. Men who would also want sons? What if your son is ugly? Women who would want both daughter and son? Can they ensure that their son will have a nice life? They cannot. Even if those women/men go for someone with model tier looks, they will likely be less good lookin than them. And someone else will always be better looking than them. Better finances than them.
There is no winning for anyone longer term like this. It doesn't matter if you're the richest person. Or the best looking one. Someone must lose in today's game. And if you don't lose today, someone from your descendants will. Why?
Humans are intelligent enough to understand these things, and we're likely the end of prime biological evolution. The next step is obviously not humans. What's there to fight for?
Nothing. Maybe bear the fruits of the collective hard work ancestors have done? As peter thiel said, competition is for losers. Stop competing in a rat race.