Download all files from https://drive.google.com/drive/folders/1JJaGA9Sb5LLdb-FWo1Ov5U0riWg1lCSD

Turn off your Internet (WiFi) or plug out your Ethernet cable, and disable your antivirus if you have one.

Go to Finder, and double-click on the folder which is called "Image-Line.FL.Studio.v20.8.3.1574.macOS.12". Double-click on "Install FL Studio.pkg" to run it, and install FL Studio. DO NOT OPEN FL STUDIO YET.

Now, open "FL Patch.dmg". Drag "FL Studio" to the "Applications" folder as displayed. Choose the "replace" option.

ONLY IF YOU ARE ON M1 OR M2: Go to Finder, then in the sidebar, go to "Applications". Scroll down if needed, and right-click (on a MacBook without a mouse, this would be Ctrl + Click) on "FL Studio" and click "Get Info". Make sure the box beside "Open with Rosetta" is checked.

Finally, open FL Studio. In the taskbar near the top, go to Help then About (use https://prnt.sc/4sU4kbgX48rm to see if you're doing it correctly).
Now, click "Unlock FL Studio" as you can see from this: https://prnt.sc/M-9Hg3AHxOIX.
Click "More..." under "Unlock with file" as shown here: https://prnt.sc/OGxUoAckPBOT then click "Load license file..." as shown here: https://prnt.sc/_CcJ9EsN3GMP
When it takes you to Finder, select "FLRegKey_20.8_Mac" from Downloads > Image-Line.FL.Studio.v20.8.3.1574.macOS.12

FL Studio may now require a restart. If it asks you whether or not you want to save the project, click "No".

Close FL Studio, and go to Documents\Image-Line\FL Studio\Settings\Internet\ in Finder and delete the file named “Default news.rss".
Make a folder in the exact same location named "Default news.rss".

Now, you can turn your Internet and antivirus on, and you can go to the FL Studio app. It may say it is licensed to someone like "VIKTOR" or "zhong", but this is a ghost account, and you are safe.