Hi. A good PD2.0 charger or power bank usually is also compatible with QC 3.0. This is what those gadgets use, and gives voltages from 3.6 to 20 V in steps of 200 mV. The max amps are up to the charger, usually good ones give 3A (at 20V) or more.
This can be hacked with any microcontroller, you just need two free pins and some resistors connected to D+ and D- of the USB.
This video from Andreas Spiess explains how it works:
Though for the price, the links you mentioned seem worth it.
In the other hand, as you only need some fixed voltages, a USB-C PD trigger module (sometimes also called decoy), as mentioned, could be better. They are less than two dollar, but they are fixed voltage. Well, not exactly: The truth is that there are two versions (one for 9/12V and the other for 15/20V), with one solder jumper you can switch between the two voltages of each type.
Then there are PD dongles that let you choose from 9, 12, 15 and 20 V with a button and have an RGB LED.
For 3V3 you'll need a linear regulator so your QC 3.0 adjustable gadgets seem better option.
Oh and QC4.0 if supported, has steps of 20 mV and broader voltage range.
Greetings.