Her study found the glymphatic clearance was mediated by a hormone called norepinephrine and happened almost exclusively during the NREM sleep phase. But it only worked when sleep was natural. Anesthesia and sleeping pills shut this process down nearly completely.
Aside from possibly becoming a dependency, I’d imagine it doesn’t interfere with sleep quality. It’s what builds up in your body to make you sleepy/fall asleep.
Too much might keep you groggy in the morning though.