No. Due to Microsoft Teams restrictions, team members must be in the Team / Channel in order to be an option to select in the Give Kudos modal (modal example below).
Here is a Help Center article on how to add or remove team members to Matter.
Can I send a kudos to someone in my Microsoft Teams workspace who is not in my Matter channel?
Learn about the restrictions for sending kudos to Microsoft Teams members outside your Matter channel.
Written by Sam Lepak