You can use
WinDbg Preview to open / analyse the CrashDump files (though the analysis is limited without access to the source code).
Visual Studio 2019 Community edition can also open the CrashDump files and will list some info and all the dlls accessed, though the last dlls listed will not necessarily be involved in the crash. It is handy checking for known conflicts, though (such as the GeDoSaTo program or Nahimic audio service).
Windows 7 shouldn't be a problem.
If you want to try troubleshooting the current game version:
Did lowering the graphics settings or a new profile and new game make a difference to the time before the game would crash?
Are you shutting down all non-essential programs before starting the game, especially anti-virus and any backup programs that may be monitoring the My Documents folder? Such conflicts don't generally have a delay before they start, though.
For example, a few people have had BitDefender block the game from being able to create files and folders, which has caused issues when saving, though usually errors rather than crashing. In those cases, including both the game executables and Larian Studios My Documents folder in BitDefender's trusted app and directory sections would fix the problem (Advance Threat Defense, Ransomware Protection / Safe Files, Application Access).
Windows Defender has also caused issues; in that case an exception for the game can be made in Start, Settings, Updates & Security, Windows Security, Virus & threat protection, Virus & threat protection settings, Add or remove exclusions.
Try browsing to the '..\Documents\Larian Studios\Divinity Original Sin 2 Definitive Edition\LevelCache' folder and delete the contents. A corrupt file there can cause problems when saving or loading.
Try exiting out Steam/Galaxy, if applicable, and starting the game directly from the '..\Divinity Original Sin 2\DefEd\bin\EoCApp.exe' program file, by right clicking and running as administrator.
Try creating a new Windows administrator user account (either with the My Documents folder in the default location, or on a different drive, if available), switch to that account and try starting the game from there, directly from the executable, and test in a new game.
Try doing a clean boot and then test the game. Click Start, or hit WinKey-R, type in msconfig and hit enter; in the General tab, click Selective Startup, uncheck Load startup items (if required) and leave Load system services and Use original boot configuration options checked. Next, click on the Services tab, check the box to Hide all Microsoft services, then click the Disable All button (maybe make a note of which are currently enabled/disabled), then click OK and reboot the computer.
Run msconfig again to switch back to the normal boot configuration.
