Ha! DIY......all you need is a cnc machine with which to build a custom crown, and then the ability to press stanchions into that crown, along with all of the clearly warranty voiding work on the lowers.
This is kinda like saying "McLaren engineers' DIY Formula 1 gearbox".
Back in the day, I used to post on the interwebz how I thought suspension was actually more important in the winter than in the summer, due to "frozen footprint" riding surfaces, increased percentage of ride time in the saddle, and sensitivity of cold hands to jarring handlebars.
But that was before everyone started riding around on 4.8" tires at 6 PSI.
So now I'm wondering if there is really a strong argument for a suspension fork that has less travel than the front tire give on a typical impact.
But I know nothing of fatbiking needs, so I will now fall silent.
I have to say that when you hit patches that have lots of footprints or have frozen and thawed to create a crater filled landscape, even with fat tires it can be somewhat jarring.
I would not want suspension on my fatbike nonetheless.