Stop charging your phone overnight

Feels like unnecessary worry. The phone are smart enough and battery replacements are a thing if you do keep the phone 2+ years

Besides, if the argument is heat is the issue then surely a 500mW old school charger overnight is precisely the way to go?

Absolute dreck. Here is the level of trustworthy info you'll find in this affiliate marketing piece masquerading as content: "...even though that increase might only be a few degrees above room temperature, doing this overnight, every night, doesn't seem smart to me. So, I've radically changed how I charge my iPhone." [Emphasis mine. Affiliate linkfest follows this stunning revelation that you should change the way you charge your phone because of the shill writer's "feels"...]