Flow is great BUT the 30 day to live limit does not really address real world business needs.If Microsoft are serious about getting people to use Flow as a business tool, then they need to get serious about the type of processes that businesses have. Even a simple FOI request can take longer than 30 days to complete.
You can now do this with the new Create Approval (v2) action. Read more here: https://flow.microsoft.com/en-us/blog/2019-release-wave-2-plan-and-may-updates-for-microsoft-flow/