Try verifying local files, for the game and editor (though reinstalling should have fixed any issues with missing or corrupt files, especially if you made sure the install folder was removed / empty after uninstalling, or installed to a different location): in the Steam library, right click on the game and select Properties, switch to the Local Files tab and then click on the 'Verify Integrity of Game Cache...' button, then the same for the editor.
Is there any difference if you try to start the editor directly from the '..\SteamApps\common\The Divinity Engine 2\DefEd\DivinityEngine2.exe' program file, by right clicking and running as administrator?
Do you have the same problem with a new project, or in the sandbox?
Can you start the Classic version of the editor?
You may want to check
Larian's Discord, as well. There are other modders there, and possibly people from Larian who can offer modding support.
