With the mod: "All the Overhauls Mod pack" enabled, and ONLY with that specific given mod - i.e. all the submods don't cause the problem - I get the error:
Failed to load mods: SE_xors_tweaks_fork_fox/data-final-fixes.lua:80: attempt to index field 'kr-enriched-iron' (a nil value)
stack traceback:
SE_xors_tweaks_fork_fox/data-final-fixes.lua:80: in main chunk

No idea why; I tried seeing if there was a mod option that I could toggle, but there was not for this given thing.

I really like this mod and would like to use it with ATOM if at all possible.
I will also continue researching it on my end - but I don't code so, yeah, what I can figure out is limited.

Fixed in the newest release. ATOM removes some of the recipes and techs added by K2, so checking whether K2 is enabled is not enough to make sure those recipes will exist.

I am not planning to support ATOM beyond a basic smoke check. Balancing for SE and K2 already is a lot, and I don't really want to dig into whatever they are doing over there to make sure my recipes don't cause some sort of infinite loops.