In most cases flow connecting to the Dynamics 365 Fin&Ops instance would connect to the same instance for all actions in the given flow. I would even say in the given environment. Now instance has to be selected on each action individually and cannot be managed for the whole flow/solution/environment at once. It is also not possible to use a variable as instance URL as then some actions do not work anymore, like "Create record".
In my oppinion the best way to solve this would be to move the instance URL out from individual actions in to connection information. Connections can be set when transferring the solution from one environment to another, and it would work also for managed solutions.