The iPad Air 4 ships with a 20W USB-C charger vs. the iPad Pro's 18W charger
About Apple USB power adapters - Apple Support
USB-C for iPad Pro: Everything you need to know | Cult of Mac
Belkin BOOST↑Charge Pro USB-C Wall Charger 20W with USB-C to Lightning Cable (1.2m) - Apple
Anker 551 USB-C Hub (8-in-1, Tablet Stand) - Anker US
18W USB C Fast Charger for 2020/2018 iPad Pro 12.9 Gen 4/3, iPad Pro 11 Gen 2/1, iPad Air 4, Google Pixel 4 XL/3a XL/3/2, Samsung Galaxy S20/S10/S9, PD Wall Charger with
ACASIS 65W GAN USB C Power Adapter, Type C Power PD Fast Wall Charger
USB-C Charger, RAVPower 2-Pack 30W Power Delivery Wall Charging Adapte
The best USB-C charger for your MacBook | Macworld