How do you manage that with magsafe/qi 2 chargers if you want to benefit from the greater efficiency and magnetic alignment? They’re all USB-C, and you can’t trivially buy USB-C chargers that are good for only 5W.

My phone doesn't support magnetic alignment, so I'm not really concerned with that. While I can't speak for other phones, my S24 has a setting that limits charging power to 10W, which is fine enough for me. I'd love a 5W limiter, though. The rest of the formula is a combination of Apple and Ikea. Stick to the name brand stuff, the horrors within the average 10-30W USB charger would make any electrical engineer cower in fear.

I really like Ikea's cheaper Smahagel chargers, by the way. They have very good electrical separation, they're cheap, and only run at 5W. The way they're shaped makes it easier to cram a bunch of them into a power strip, which is nice. Can't speak for the USB-C Ikea chargers though.

We have a bunch that are USB-A to micro-USB to the charger?

If you want to use the newer chargers, I’d think you’d want cooling and airflow. At some point, I want to build a MagSafe stand with a low RPM silent fan on it.