When Nietzsche praises egoism it is always in an aggressive or polemical way, against the virtues, against the virtue of disinterestedness (Z III “Of… - Gilles Deleuze

This is Nietzsche’s twofold struggle: against those who remove values from criticism, contenting themselves with producing inventories of existing values or with criticizing things in the name of established values (the “philosophical labourers”, Kant and Schopenhauer, BGE 211); but also against those who criticise or respect values by deriving them from simple facts, from so-called “objective facts” (the utilitarians, the “scholars”, BGE Part 6). In both cases philosophy moves in the indifferent element of the valuable in itself or the valuable for all. Nietzsche attacks both the “high” idea of foundation which leaves values indifferent to their origin and the idea of simple causal derivation or smooth beginning which suggests an indifferent origin for values. Nietzsche substitutes the pathos of difference or distance (the differential element) for both the Kantian principle of universality and the principle of resemblance dear to the utilitarians. “It was from the height of this pathos of distance that they first seized the right to create values and to coin names for them; what did utility matter?” (GM I 2 p. 26)

Nietzsche’s break with Schopenhauer rests on precisely this point; it is a matter of knowing whether the will is unitary or multiple.

We're tired of trees. We should stop believing in trees, roots, and radicles. They've made us suffer too much. All of arborescent culture is founded on them, from biology to linguistics. Nothing is beautiful or loving or political aside from underground stems and aerial root, adventitious growths and rhizomes.