MacOS turns on Modem mode on iPhone. How would I disable that?

iPhone personal hotspot is listed in the list of WiFi networks on my mac even though Allow Others To Join is off and personal hotspot is off. MacOS turns on Modem mode on iPhone when I click on "connect". How would I disable enabling personal hotspot by any means other than exoplicit enablement in the iPhone settings? (Just got a bill for mobile internet traffic so that's no idle curiosity)