Use Sequence parameter to sort ListView Command Set in menu
The sequence parameter (int) in the custom action schema should allow us to sort the action within the whole menu.
Actually it's only used to sort SPFx actions among themselves.
Related issue : https://github.com/SharePoint/sp-dev-docs/issues/4121
Charles Simard commented
That would be great indeed !! I can't believe this hasn't been implemented yet :(