12.9 iPad Pro 2018 cable/charger

Apple disclosed in an online interview that this iPad can safely handle 45w charging, 45w being the max threshold. Well the 18w charger it came with is fine with me so far since I’m used to the 2.1amp chargers ive been using on my original 12.9 pro. My question is for the CABLES and the power difference between the gen1 and gen2 cables that are being sold. Does it matter what usb c cables I buy when it comes to actual POWER being delivered? I don’t care about data transfer or connecting to something, this will ONLY be used to charge my iPad. There is a wide range of PD chargers from 18-27-30-45w that I can buy. 30w seems fine to me but pointless if certain cables don’t support that wattage. I’m finding it difficult to find information on the range of power transfer between the various cable generations/formats.