iPhone X Bluetooth keeps cutting out in Jeep with U-Connect

I have an iPhone X. I drive a Jeep Wrangler with U-Connect. The phone initially worked in the car with Bluetooth through the U-Connect system - able to make & receive calls, stream music in the car. Then it stopped working. I could also not use my old iPod classic anymore through the auxiliary setting - it had been working previously. It just kept cutting out/switching off and going back to radio if I tried to stream music, play music through the iPod and if I made/answered calls, the calls stayed connected but the Bluetooth kept cutting in & out. I took it to the Jeep dealer. Phone software & U-Connect software was up to date. They couldn’t find anything wrong but booked it in to try & work on it. Then on the day it was booked in, it started to work again, so I cancelled the appt. It worked fine for a few mths. Now the same issue is happening again. Software on phone & U-Connect is up to date.

I have connected my husband’s Google Pixel 2 phone to the U-Connect today & it streams music fine & makes calls fine. So I think it must be an Apple connectivity issue?