On 2023-08-28 08:25, Carlos E. R. wrote:
I'll use USB if I'm going to be tethered for a
while, so that I don't run down the phone battery.

USB charges the phone at the expense of the laptop battery 😛

Wifi on the 5Ghz band seems to drain very slowly for me, with the phone
just a foot away. Still at 100% after 25 minutes. I did not check
yesterday the figures.

The thing is, BT power is negligible, that's why I was tempted.

If I'm tethered long enough to worry about the battery, my computer is plugged into AC power.  Years ago, I used the WiFi tether and then forgot to turn it off.  I was left with a dead battery.  These days, however, the WiFi hotspot will turn off after 10 minutes without a connection.

BTW, my own computer, an eleven year old ThinkPad E520, only supports 2.4 GHz WiFi.  😭
It also doesn't have Bluetooth.