Actually I haven’t been able to get Bluetooth 5 dongles to work on Linux. I only have success with Bluetooth 4 dongles.
What are you going to use the Bluetooth dongle for? Connecting Bluetooth peripherals, or headphones? If it’s exclusively for Bluetooth headphones, using a Bluetooth audio dongle (which is detected as a USB audio device in Linux) works much better than using the Bluetooth 4.0 usb dongle for audio purpose because you can use low latency aptx codex and Bluetooth 5 without messing with random drivers from some github repos