I will quote jorimt who originally posted it. So far it has worked for a few of us in this thread, who previously could not run the game in DX12
For it's worth, I found these steps online, and it worked for me (couldn't launch with DX12 previously either):
1. Search "Apps & Features"
2. Click "Optional Features"
3. Click "+ Add a feature"
4. Click "Graphics Tools" > "Install"
5. Relaunch game in DX12
Seems like my system and/or the game was missing some DX12 dependencies (even though my Windows Updates are all installed).
May or may not work in your case, but worth a shot.
Scan Line Sync Guide/Thread, FYI: