I've had so many problems with the personal hotspot on my iPhone xs max.
It really annoys me that this seems to be a known problem, and has persisted for a long time without a fix.
Sometimes I have to repower the iPhone, reset network settings, toggle airplane mode, change the device name, just to get the hotspot working. It seems entirely random too, as to which action fixes the problem.
https://www.engadget.com/2020/03/22/apple-ios-13-personal-hotspot-issue/

