Macbook charging with USB-C Monitor
Normally when you provide more watts+volts+amps the device will simply draw less . Its the opposite that brings trouble i.e a cheap usb charger with 500mA and ur phone requires 1.0A. It will draw more than the charger can produce and heat up and more than likely damage ur phone. there are some differences in maintaining voltages steady for particular devices but thats very particular. Just make sure w.e the Dell can dish out across the board is more than the Mac charger and you should be fine