they aren't cheap, but noctua's latest 120mm fans are arguably as good as it gets, in quantifiable ways: https://www.hwcooling.net/en/noctua-nf-a12x25-g2-pwm-the-kin...

Noctua makes really good fans, I'm told. Want to get on their level and make a similar amount of money? In a world of slop, quality engineering is valuable.