Dear NTran99,
Greetings! Thank you for posting to Microsoft Community. We are happy to help you.
We went through your thread carefully and understand your concern about Power Automate flow. Since it's related to Power Automate, we would like to request you to post your detailed concern in the related community i.e., Microsoft Power Automate Community - Power Platform Community to get the detailed help from the experts.
Below are the similar thread we've found in that community and we hope it can help.
For your reference: Solved: Copying a list to another list with a multi select choice column
Solved: How to copy a sharepoint list with multiple select column in flow
Solved: Copy items from sharepoint list to another sharepoint list with multiple person columns
Please accept my sincere apologies for not being able to resolve the problem and for redirecting you to different community as the members in the category posted focus on the users with the Microsoft 365 and SharePoint concern and have limited knowledge on the Power Automate, so to get the fast and better assistance, we have redirected you in the correct path. I regret any inconvenience this may cause.
Once again, I apologize for the inconvenience this has caused. We appreciate your patience and understanding and thank you for your time and cooperation.
Hope you stay safe and healthy.
Sincerely,
Rhoda | Microsoft Community Moderator