I suggest to extend the For a selected item of the Sharepoint connector to be usable also in non-default environments (https://docs.microsoft.com/en-us/sharepoint/dev/business-apps/power-automate/sharepoint-connector-ac...).
Nowaday I can create this kind of flows in a sandbox environment but I can't test it if it's not in the default environment, and I think this is a very huge limitation.
Also, importing my flow in a Production environment that is not the default one, the flow doesen't work