Let's clear some things up:
Wireless Charging refers to the Qi wireless charging standard that allows you to charge your phone without directly plugging it in. You place it on a charging pad, or in the case of the new iPhone 12, the MagSafe charger will magnetically align it for you. You have to plug the base (transmitter) into the wall - it can't obtain power from thin air.
USB-C charging conforms to the USB-C Power Delivery spec in which it negotiates higher charging rates. To get those higher rates, you need a USB-C charger rated to at least 20W. You can use a higher one with no problem. If you use a lower rated one (i.e. the 5W charger) but, you won't get the faster charging speeds; it may not even charge at all.
The "regular" USB type A charger (that everyone has) can typically supply up to 12 watts of power. You can use a charger that supplies more, but the phone will not draw any more than 12 watts. Again, I recommend, using chargers with higher wattage ratings.
Anker PowerIQ is Anker's technology that identifies what it's connected to so that it can deliver the maximum charge to the device connected. The first generation of PowerIQ delivered up to 12W and PowerIQ 2.0 can deliver up to 18W. These really have nothing to do with Apple's products per se other than they are compatible.
The charger (the thing that plugs into the wall) is required; period. Regardless if it's USB-A or USB-C, you can always use a "larger" charger than what is called for, in fact, I recommend it. A USB-A charger will typically max out at 12W (5V @ 2.4A). A USB-C charger will go up to 20W.
If you go wireless, you still need a charger (USB-C) and the maximum you'll get is 15W using MagSafe and only half that (7.5W) using a regular Qi charger. No matter what, you still need to plug the Qi base into the wall and the sizing rules still apply - get an adapter "larger" than what you need (i.e. get at least 20W). You can use a USB-C MacBook charger rated at 91W with no problems whatsoever. The 5W charger that came in the iPhone SE box will not cut it.
You can use either the new USB-C charger with Power Delivery or your can use the older USB (type A) chargers that supply 5V at 2.4 Amps