Thanks for all the help.
As mentioned in my second post, I found a workaround. so I just want to sum it up, in case someone else has this problem:
- USB cable is not faulty (tested with several cables)
- The MTP selection drop down does not show up, with “developer settings” disabled
- The following workaround enables the MTP selection drop down
- Turn on “developers settings”
- Change setting “USB configuration” from “charging” to MTP
- Turn off “developers settings”
Thanks all