1.) Set the default auto expire in Teams Admin Centre (Admin)
2.) You can create retention labels and push these into OneDrive for users to use on the video (I.e. 1 year, 2 years, 3 years) (User) Retention labels supersede the default expiration time
3.) You can auto label recordings using KQL (Admin)
In terms of if you can modify the expiration time. Not in File Explorer or Teams. It's all within OneDrive or Admin Side.
Hope that answers your question