I think my cheap choice of wireless charger is to blame; I'll have to try this out again with something more legitimate.

So far, this seems to be the best one I've seen for a combination of name recognition, fast charging support (which is still pretty hard to find), and not being ugly as sin: https://www.logitech.com/en-us/product/powered-iphone-wirele...

You can find cheaper $15 ones in a similar form factor on Amazon from Seneo, but it seems to be a crapshoot whether any specific unit will last long-term or have misaligned coils that give off an annoying whine.

Thanks, I'll definitely check that out

On the cheap side, I've had luck with the Comsol Wireless Charging Stand. I've used them with both a Nexus 5 & a Galaxy S8. Unfortunately it appears to have just been discontinued (currently on clearance sale), though I'm not surprised as it looks like a knock-off of a Samsung design:

https://www.officeworks.com.au/shop/officeworks/p/comsol-qi-...

At least with first generation Qi devices I think it was the device and not the charger to blame. I have a branded Lg charger and my Nexus 4 would occasionally overhead on it depending on how it was positioned. I eventually abandoned it and gave it to my wife who used her Nexus 5 with it for years and never complained of overheating.