Hey there, Russell Ian Bulatao
Can you try clearing the cache and cookies in your browser. Then Azure DevOps again. Once you have signed in, please click onto Project settings > Permissions > Users > Select the user you want to change
Once you have opened the user's profile up. You can see permissions, or member of. You will want to click onto the group you wish to remove them from, then click remove.
You can choose to add them to another group through the add option. Then select which group you wish to add the user to. You can customize the individual permissions the user has through the permissions tab. For more information about this, please look at this article here: https://learn.microsoft.com/en-us/azure/devops/organizations/security/change-access-levels?view=azure-devops-2022&source=recommendations
Hope this helps,
Nathan