I'm using my old series 5 Apple Watch charger on 5w iPhone charger in the bathroom. No big deal. I'm even using a slow 3 in 1 iPhone, Apple Watch, air pods charger near my bed.
I’m using the Anker 543 (65W II) for my Apple Watch and iPhone. It’s got 2 USB A ports, a 20W USB C port and a 45W USB C port. I’ve even used it to charge my MBA in a pinch.