HanSewLow: I already patched up to 3.6.51.1333jajp before making the original post.
The installation method shouldn't make any difference, then.
Try deleting the config.xml file in the '..\Divinity Original Sin 2\bin' folder, as well as the contents of the 'C:\Users\<UserName>\AppData\Local\LarianLauncher' folder (copy and paste %LocalAppData%\LarianLauncher into Windows Explorer to quickly open that folder).
After that, try starting the launcher from the '..\Divinity Original Sin 2\bin\SupportTool.exe' executable (there will be a delay of a few seconds before the launcher starts, if this helps, as the contents of the LarianLauncher folder are rebuilt).
If that doesn't help:
If you check the Event Viewer, does that give an error code or 'Faulting Module' file name for any event related to the error?
- click Start (or WinKey-R), then type "event viewer" into the search box. in Windows 10, 'event' should bring up 'View event logs'.
- after starting the Event Viewer, expand 'Windows Logs' in the left column and select 'Application'
- in the center column, look for a recent error for the game (maybe sort by Date and Time, or search for 'SupportTool')
- check the information under the 'General' tab below the list of events, starting with "Faulting application name..."
Please email supportdos2@larian.com with a dxdiag report (WinKey-R, type in dxdiag and hit enter, then when it finishes loading click on the 'Save All Information...' button and save the report somewhere handy). Also check the 'bin' folder for the launcher for the gold.log file, and if there are any 'CrashDump' files being created, zip a few together to include.