I use Seasonic ATX PSU's in my 2u chassis: https://seasonic.com/product-category/industrial-products/pc-atx/I have some Seasonic PSU that give you the option of hybrid or not, and in hybrid the fan does turn off but honestly any seasonic PSU or EVGA 2 or 3 will be silent enough even with a fan to be not noticeable in an office / desktop workstation environment.
When it comes to 2U+ servers and desktop/ATX style PSU ideally you want a rear-exiting fan not a top/bottom like SOME consumer ATX style PSU will do. I have a handful of 400w or so maybe 350w iirc, I forget exactly that are specifically made to intake in chassis and exit rear PSU these are ideal for 2U/server chassis.