Also just for fun, Apple introduced a hidden feature to see how busy a Wi-Fi channel is on macOS 15! When you're connected to Wi-Fi, open a terminal and type `sudo wdutil info`. Look for the "CCA" percentage. The higher the percentage, the busier the Wi-Fi channel.

@simonbs I'm 100% with you. There’s something even more insidious about iPhone’s tethering: it stubbornly uses Wi-Fi channel 149. In a crowded train filled with people working on their laptops with Wi-Fi tethering to their iPhones, the tethering becomes unusable even when the 5G signal is full. My tethering's network performance restored straight away the moment I got out of that train.