I have also been looking for a solution for this for months, and I FINALLY came across the cause of it (which is the weirdest bug in my opinion). If your Windows PC username has any special characters in it, for some reason the launcher won't allow the game to launch. My username on Windows had a "♥" in it, and once i changed the username to letters only, it worked just fine. If this applies to you, steps to fix are:
1. Win key + R
2. Type netplwiz and hit "Ok"
3. Under "Users for this computer", click on the account you're logged into, click "properties" and change the "username" field to something without special characters.
4. MOST IMPORTANT STEP, RESTART YOUR PC.
5. try launch the game now hope this helps you or someone else out there who was struggling like me