The Meizu Pro 7 Plus phone has a unique way of charging which uses Meizu's mCharge 4.0 fast charging technology over the USB Type-C port. The mCharge technology is most likely based on MediaTek's Pump Express 3.0 that enables USB Power Delivery based communications to achieve over 23W of fast charging. But make sure to use the Meizu's supplied USB Type-A to Type-C cable with the Meizu Pro 7 Plus's own USB Type-A based AC charger in order to deliver over 23W to the USB Type-C port of the phone.
Since the Meizu Pro 7 Plus also supports charging through USB Power Delivery over USB Type-C, we'll see if it can be charged using the Google 18W USB-C Power Adapter which is a USB Power Delivery based charger. When the Google charger is connected to the Meizu phone on a fully depleted battery, the charger repeatedly displays its source capabilities of 15 watts (5 volts @ 3 amps) and 18 watts (9 volts @ 2 amps) through the Granite River Labs GRL-USB-PD-A1 test software.
After a hard reset we can see the Google 18W USB-C Power Adapter again offers 15 watts (5 volts @ 3 amps) and 18 watts (9 volts @ 2 amps) which the Meizu Pro 7 Plus goes on to request and establish 13.5 watts (9 volts @ 1.5 amps) with the charger.
We further observe that the Meizu Pro 7 Plus from zero charge actually pulls an initial 0.9 amps current at 5 volts while the phone is off or in sleep mode. We then observe the current changes rapidly as the phone first requests 13.5 watts from the Google charger. The current becomes more stable after 40 seconds for the phone to charge at around 13.5 watts (9 volts @ 1.5 amps). However the current later drops again and bounces around 0.9 to 1.3 amps before charging returns to 13.5 watts (9 volts @ 1.5 amps). The same cycle can be seen repeating as charging goes on.