You know what I think about metronome marks: they're right for a single bar, like 'roses, with a morning life'. Only there are 'those' who don't hear music and who take these marks as authority to hear it still less! But do what you please.
Debussy For more on rubato and tempo in Debussy, look here: https://www.djupdal.org/karstein/debussy/method/m06.shtml