How to remove digitizer

I don't know for sure, but it's likely the digitizer can't be separated. Most car stereos use a screen that has a unified LCD/digitizer assembly, unlike some cell phones where the components can be replaced independently. Check the service manual to see if there is a separate digitizer part number. JVC probably just lists the entire screen assembly as one part. In theory you could replace just the digitizer but it would be challenging to find the right part and surgically separate the assembly (which is probably glued).