It comes with a Y-cable. It is recommended to use both, but it is not explicitly prescribed. It also depends on how much current your connection can deliver.

It also works perfectly for me. But there can be problems... Try another USB port to see if the device is recognised there. (What exactly is not working?) Otherwise it is worthwhile to run an update while the drive is connected. It might work wonders. Or update your USB drivers :). Also make sure that the drive can draw power via USB. With most laptops, the power supply is sufficient so that you only have to connect the "longer" USB cable and the shorter one can be left dangling.

Hello Michael, Blu-Ray: yes, 4K: unfortunately no. For this I recommend: Samsung UBD-K8500 3D Blu-ray disc player. Also available here in the shop for CHF 185.

CD/DVD write/read no problem. However, I have not yet used a BluRay disc. Upscaling would probably be more on the software side.

according to google image search it needs 2 usb ports for operation

Yes, without any problems. I use it myself with a Windows 10 PC. I am satisfied!

There is not only one burner for optical drives. If a device can burn a Bluray or a DVD, then it can also read it afterwards. Otherwise it would make little sense.