Newer Dell laptops charge via USB-C PD, and work with any compliant charger you'd like. Actually that's not quite true - I believe they require 20V support, and like most things USB C, just because its "USB C PD" compliant, doesn't mean it supports 20V (most OEM phone chargers dont, for example).
What's funny is MacBooks don't require 20V. I've never tried with an iPhone charger, but I've definitely charged MacBooks overnight with a common 12W iPad charger (using one of those USB-A-to-C cables).
