Does 248k play nicely with k2 and se? I wasn't aware this combination was compatible or coherent.

Sorry for the late reply.
Yes the combination works, at least I haven't found any errors or complications yet. But it is very grindy, especially in the endgame.

I think I found that there are some odd things like 2 different kinds of lithium, one from 248k and one from k2.

The combination of mods is not perfect yes.
Duplicate resources and recipes I have also noticed, but I have so far not encountered any game breakeing things