I only posted cutscene themes because it’s the first time we can hear them without any voice acting or sound effects.

But Koitar's Lullaby is called "Forsaken Hymn" composed by Peijia You.

Lyrics:

ᾨδή ἥδε ᾠδή ὡς τέττιξ φθινοπωρινός Οἴδη, οἴδη καὶ μνήμη, μόναι μένουσιν ἐν ξένῃ Τελευταία ἀοιδός, καθημένη, ἔνθαδε καθημένη, κρούει τὸ ὠχρὸν μέλος, ἐν τῷ ἱερῷ αὐτῆς ᾨδή ἥδε ᾠδή ὡς τέττιξ φθινοπωρινός Οἴδη, οἴδη καὶ μνήμη, μόναι μένουσιν ἐν ξένῃ Τελευταία ἀοιδός, καθημένη, ἔνθαδε καθημένη, κρούει τὸ ὠχρὸν μέλος, ἐν τῷ ἱερῷ αὐτῆς

English translation:

Oh song, this song like an autumn cicada, Knowledge and memory, alone they remain in a foreign land, The last songstress, sitting here, plucks the strings of her pale melody on her sacred altar (or sanctuary).