Game won't launch after Season 18 update (Steam)

As the title says, since updating to the new Season 18 update my game refuses to launch. It was working fine prior to the update. Now when clicking play, the game says running for about 5 seconds and then goes back to play. I have tried a multitude of troubleshooting, with unfortunately no success:

• Force closing Steam
• Restarting my pc
• Validating game files
• Firewall and Antivirus settings
• Closing other 3rd party programs
• Completely uninstalling and reinstalling the game

If anyone has any insight as to a possible fix that I haven't thought of it would be greatly appreciated.