On MacOS my VSCode always opens to the default welcome page and never opens any folders. I tried to set a default folder, but there doesn’t seem to be an option for that. So instead I tried to force VSCode to reopen my last files and folders. For some reasons, the settings from the Settings menu just wouldn’t do the trick. Instead I had to extend the settings.json with this little thing:
"files.hotExit": "onExitAndWindowClose"
For now, VSCode seems to always open my work folder again. Hopefully it stays like this.