Did you know that you can still recover deleted environment within 7 days of deletion by using Power Apps cdmlet Recover-AdminPowerAppEnvironment?Tweet
Learn more about the Powershell cmdlets here. It is in preview mode but users with a valid Power Apps license can perform the operations in these cmdlets. Note that you can only perform these with the resources you have access to. More information here.
Note: Environments that can be restored are environments deleted by an administrator and not those deleted by the system due to license expiration and other scenarios.
Let me know how it goes on your end. Enjoy!