CarPlay keeps reverting to Wi-Fi hotspot instead of cellular data

Using CarPlay, new EV macan, new iPhone, latest iOS

wireless CarPlay: intermittently the phone gets no data (is trying and failing to get its data over the WiFi connection to the car)

intermittently: will pop up “not getting data through this hotspot” error on the phone and ask if I want to use cellular, duh, yes

but: doesn’t remember and regresses to trying to get data over WiFi again

other discussion threads suggest: forget the car WiFi on the WiFi menu on the phone. This solves it temporarily, and mostly still handshakes (surprisingly) over WiFi for CarPlay

but: even with no action on user side, phone and car start reconnecting on the WiFi (no prompt or approval by user) and problem comes back.

if I keep the network but change to “don’t automatically sign in” on WiFi settings for the car’s hotspot, it will durably keep it from connecting but now won’t CarPlay wirelessly at all

ChatGPT tells me that if I forget the network in WiFi it will still CarPlay wirelessly (they all handshake over Bluetooth, then communicate WiFi, even if I don’t have the hotspot.) and this is consistent with other commenters and my experience that forgetting the network in the WiFi list works (still get wireless CarPlay!) but ChatGPT and those threads don’t resolve the problem I have that the hotspot keeps adding back as a WiFi network, without permission or approval

any ideas? My only:

-give up and just use wired only

-try paying $20/mo for Porsche hotspot she if it successfully gets the data that way. Waste of money but chump change compared to the massive depreciation in a luxury EV anyway so might as well live it up.

[Re-Titled by Moderator]