There is an existing thread in the Forum regarding this topic where you could vote for: Sort / Collate Projects By Owner
If you are in a Premium Plan, one workaround could be running an advanced search for all Tasks in Projects owned by a certain person (you could add other filters if necessary). Once you have the search results, you can sort it by Project. Please see screenshot below:
I hope this helps! Please let me know if there is anything else I can help you with!