iPhone unable to connect to IoT devices after restore

I happen to have a weird connection issue that I believe is related to my iCloud profile.

For some reason my iPhone 13 Pro Max is not able to connect to external devices over an ad-hoc WiFi connection.

1st example: cannot connect the phone using the "Porsche Track Precision App" to my car.

2nd example: cannot connect the phone to an external OBD dongle

Both these use-cases require joining the ad-hoc WiFi network created by the other device (car in the 1st example, OBD dongle in the 2nd), then use an app to connect to the device.

I tried with other iPhones (e.g. my wife's iPhone 12 Pro Max) and it can connect correctly in both cases.

I also managed to connect using an old iPhone XR (that was also configured with my wife's profile). I then decided to reset this old iPhone XR and restore it with my iCloud backup.

After restoring with my profile, the iPhone was not able to connect anymore.

I tried to reset the network settings, reset all settings with no luck. I also verified there was no "stale" VPN profile installed (I read in other posts that it could cause issues with network connections) - again no luck.

At this point I'm pretty sure this is a problem related to some obscure parameter or setting that is restored when I restore the iPhone using my iCloud backup - but I have no clue how to find out for sure and of course no idea how to fix it.

Has anybody else experienced something similar, and/or does anybody knows or has suggestions on how to fix this issue?

Thank you.