How to charge a phone by plugging into my Mac

when you use an adapter/Dock, that device decides how much power to allocate to each connection, and hogs some for itself. Try bypassing the Adapter/Dock and using a direct plug in cable to your phone.

what connector on the phone?

Low power devices like phones can charge overnight on the 5 volts, up to typical 500 milliAmps power normally supplied over USB-C by default. The ports on the Mac MAY provide as much as 900 milliAmps in some cases when used directly, but NOT when used through a docking device or complex adapter.

Every 'smart' device that uses USB-C Power Delivery Protocol can also Request higher voltages and currents, but these are negotiated with the supplying power adapter or powering device. So turning off phone fast charging will merely keep your phone from Asking for higher power. The powering device already has the ability it say NO.