Test with MacBook Pro 17' Late 2011 / OSX 10 (Yosemite)
The dongle works out-of-the-box, but I had to manually switch the system to the USB dongle.
In this discussion in the stackexchange.com forum some methods are mentioned.
https://apple.stackexchange.com/questions...
I used DavidD's answer because I think it is the most reliable.

Here is the whole procedure:

Note the MAC address of the internal Bluetooth controller:
1) In Settings/Bluetooth, activate the option at the bottom "Show Bluetooth in Menu Bar" (maybe it's written slightly differently - I'm using an English OS)
2) Press the Alt key and click the BT icon in the Menu Bar.
3) Note the address.

Instruct the kernel to use the external controller.
1) Remove the Bluetooth devices in the settings/bluetooth for all users (not only deactivate them, but really delete them from the list).
2) Switch off Bluetooth devices if possible
3) Log in as administrator user
4) Switch off Bluetooth on Mac
5) Plug in USB Bluetooth Dongle
6) Switch on Bluetooth on Mac
7) Start the app Terminal in Utilities and enter the following command in one line (don't mistype anything there!!!), execute with Enter key. You will be asked for a password: enter the same admin password of the logged-in admin user. The password is entered blindly. In case of mistyping and/or insecurity, simply type the Backspace-Delete key in superset and enter the password from the beginning. Before confirming with the Enter key, the procedure can still be cancelled with Control+C.

sudo nvram bluetoothHostControllerSwitchBehavior=always

8) Restart
9) Note the MAC address of the Bluetooth again: it must have changed. If it didn't work, do step 6) only after 8).
10) Pair the Bluetooth peripherals individually.

Reset: sudo ...=never

Macbook Pro 15' mid-2012 i7 nonretina auf Mojave 10.14.6. : bei mir wird der zwar erkannt, aber er erkennt mein Magic Trackpad und Magic Keyboard nicht, trotz procedure von DavidD
https://apple.stackexchange.com/questions...

(To force your system to use an external Bluetooth controller instead of the internal one, open Terminal and type:
sudo nvram bluetoothHostControllerSwitchBehavior=always
then reboot. To revert to the default OS X behavior, type:
sudo nvram -d bluetoothHostControllerSwitchBehavior
You may need to turn off (or un-pair) Bluetooth accessories that are currently using your internal Bluetooth controller, as they can prevent the dongle from being detected ...)

Ich konnte die devices nicht mehr unpairen, weil der interne Bluetooth während des Arbeitens den Geist aufgegeben hat.

Zusätzlich viele Neustarts probiert sowie reset PRAM/NVRAM und SMC, Safe Boot, neuer admin user, /Library/Preferences/com.apple.Bluetooth.plist weggeworfen, half nix.

Mein Nacken fände es toll, einen Adapter zu haben. Sonst muss ich eben eine alte USB Tastatur und Maus finden ...

Just out of curiosity: do you need the adapter for a Hackintosh?

General basis about compatibility USB BT adapter with Mac:
The hardware is always compatible. The decisive factor for compatibility is a file in the OS. It ensures that the creator and model of the adapter are recognised and that the driver is automatically downloaded from the Internet and installed.
It is therefore more up to the OS than the device whether an adapter works "out of the box".
However, you can also change the file in the OS manually according to these instructions:
https://www.atpeaz.com/using-unsu...
As also described in this article, the procedure must be repeated for each update.

Note for the installation: Activate Internet connection, remove all BT devices in the settings first, switch off BT, shut down, plug in USB adapter, start Mac, pair BT devices in the settings.

Tested out-of-the-box in the following environment: OSX 8.5 (Mountain Lion) / MacBook Air 13 Mid
Delock Bluetooth 4.0 USB Adapter (USB 2.0) / Art-Nr 374315 worked.
Digitus Bluetooth 4.0 (USB 2.0) / item no. 374315 did not work.

As soon as the graphics card is replaced on the other Mac, I will test these two adapters on a MacBook Pro 17 Late 2011 with 10.10.x.

According to our information, this adapter effectively only works with Windows.