iPhone 11 Pro Max automatically disconnects after about a minute from Carlinkit (WiFi connection)

Recently I bought a Carlinkit V3 device for my car. It is a product that makes a non-wireless CarPlay car a Wireless CarPlay car.

How does the Carlinkit work:

Once the dongle powers-up, the dongle tricks your CarPlay system into thinking your iPhone is connected by wire to your system/receiver. Meanwhile, your iPhone thinks it’s connecting to a wireless CarPlay system (the dongle), so it then transmits CarPlay wirelessly over Bluetooth (for the initial hand-shake) and Wi-Fi (for audio and video data) to your car system/receiver via the dongle. 

The initial start-up works fine. I can connect with it via Bluetooth and everything works normal. But after about a minute the CarPlay screen freezes and the music stops. It has disconnected. This is the WiFi-signal that has been disconnected. So first I thought the Carlinkit was corrupted and I sent it back to the manufacturer and asked for a new one. But the new Carlinkit had the same problem. So I tried the Carlinkit in a different car. Maybe it was my car that had problems with the Carlinkit, but it also didn't work. Then I tried a different iPhone, my brothers and my girlfriends iPhone. They both worked fine in both cars. So it has to do something with my iPhone.

So I continued. I tried the following steps:

• Reset to factory settings via iPhone.
• Reset to factory settings via a Mac.
• Reset the network settings on my iPhone.
• Reset all settings on my iPhone.
• Use a different iPhone with a back-up.
• Use a different iPhone without a back-up, but with my Apple-id.
• Disable WiFi-assistance in settings under Mobile Network on my iPhone.
• Disable Private-relay in iCloud on my iPhone.
• Disable Keychain in iCloud on my iPhone.
• Disable Networks and wireless under Privacy, Locationservices, System on my iPhone.

These all didn't work. So what did work?

• Use a factory clean iPhone (without a back-up) without logging in to my Apple-id.
• Use a factory clean iPhone (without a back-up) with logging in to my Apple-id without a simcard.
• Use a iPhone with a different Apple-id.

So it is clear that my Apple-ID/iCloud is the problem. This is how far I came in the digging to a solution.

By the way, I don't have any issues with other WiFi networks that are routers, access points or hotspots. I do have problems with devices that broadcast a WiFi-signal, but doesn't provide data for a internet connection.

Can somebody please help me?