Odd, so the MacBook talks to the iPhone over wifi once you put in the correct info for the hotspot. Have you tried taking the MB to somewhere else (like a McDonalds) and making sure the wifi connects there also? If that is the case, it might suggest you really do just have the wrong info for your wifi network at home on the MB
Assuming your iPhone is updated to the latest iOS, and can get on your home network via wifi (i.e. confirm that with cell date off and try to reach a website), then go to Settings > Wi-Fi, click on your home wifi network name and then tap the "i" (for info) button. When you see the "bullets" for your wifi password, touch and hold your finger on that. Face ID should kick in to prove it is you and then the "bullets" should change to show the actual password that the iPhone is using. Is that the same as you are using on the MB?