Hi @Roger Roger ,
Welcome to the Microsoft Q&A platform!
Yes, setting IsGroupFoldersAndRulesEnabled to true should allow your users to create rules in both Outlook and OWA for a Unified Group mailbox. Your syntax is correct:
Set-OrganizationConfig -IsGroupFoldersAndRulesEnabled $true
After running this command, it might take some time for the changes to propagate. If your users still face issues, ensure they have the necessary permissions and that their Outlook clients are updated.
Please feel free to contact me for any updates. And if this helps, don't forget to mark it as an answer.
Best,
Jake Zhang