Have you tried switching to windowed or fake fullscreen display mode?
Try lowering your desktop resolution.
Please email supportdos2@larian.com, with the report.zip file generated by the
D:OS 2 Analysis Tool (minus the saves, since they are not relevant to the problem).
Extract the zip file somewhere handy (like the Desktop) and in the AnalysisTool_DOS2 folder, run corresponding executable. It should detect the game install path, but if not you can browse to the 'Divinity Original Sin 2' folder. Optionally run the tests first, and then generate a report (it will be saved in the same location as the Analysis Tool).
The report will contain system and game information, as well as your saved games. To greatly reduce the file size, you can delete all of the saves from the zip (double click the zip file to open it in Windows Explorer, then browse down to the ..\Savegames\Story folder).