You can configure each hub to automatically assign new tickets to one user. This setting is applied at the hub level.
To auto-assign a user:
Go to Operations > Hubs.
Click Manage on the hub you want to configure.
Under User to be auto-assigned to new tickets, select the user from the dropdown.
Click Save Changes.
From then on, all new tickets created for that hub will be automatically assigned to the selected user.
Note: If you want to automatically assign multiple users to new tickets, create a Team and select it under Team to be auto-assigned to new tickets for that hub instead.
Check out the Article: Can I assign multiple Users to a Ticket?