New Teams client upgrade in GCC

I have a GCC tenant so new Teams timelines are a bit different than regular commercial tenants. I am trying to set the Teams Update policy to hide the 'try new Teams' toggle in the classic Teams client BUT allow those users with the new Teams client installed already to still use the new Teams client. The 'Not enabled' update policy option does hide the toggle but also forbids the user from using the new Teams client if they have it installed. This scenario seems to be somethign most admins would desire so I have to be missing something  with the proper update policy setting. Can anyone offer some advice?

THX> Eric