The mod is still incompatible with pipe plus, error
Не удалось загрузить следующие моды: Error while running setup for entity prototype "pipe-to-ground-south" (pipe-to-ground): Invalid fluid pipe connections. For entity direction North connection [pipe-to-ground connection 2] collides with [pipe-to-ground connection 1]. Definition [type=normal, position={0, 0}, direction=South]
Mods to disable:
Pipe_plus 0.2.1
combat-mechanics-overhaul 0.7.2
the-one-mod-with-undeground-bits 0.1.32
Krastorio2-spaced-out 1.4.32

everything starts without pipe plus, and with it this error

AUP will not be compatible with pipe plus.

that is, they cannot be combined in any way?

No. The functionality that AUP uses to make the mod work is not compatible with mods that add pipes with fluid connections on top of each other (underground and normal). In any case, the mod combination is effectively useless since AUP fills all underground pipe spaghetti requirements that mods like pipe plus or advanced fluid handling also fill.