I tried Dvorak and Workman before landing on Colemak and eventually Mod-DHm.
Colemak just felt the most natural and comfortable. Mod-DH is suppose to be an improvement over standard Colemak and Mod-DHm was recommended when using a matrix style keyboard. I cannot truly speak to it being an improvement as I barely used standard Colemak before switching to it, but I certainly find it enjoyable.
I’ve seen some specific layout mods for programmers for both Dvorak and Colemak. However, I feel once you get a keyboard like the Atreus or Moonlander, really you can optimize your layout to improve your particular workflow.
Here’s my Atreus layout. My layout for the Moonlander mirrors this with a few bells and whistles since of course there more keys. Though, any key that I would access regularly is still placed on the three main rows and thumb clusters.