MS Teams and Flow for Sign-Off

Here's what I want to do.  Use MS Teams and Flow to track Purchase Requisitions from Engineering through the approval process and finally after approved email a link from Teams files storage to Purchasing with appropriate approvals.

But Flow under Teams is really cranky, I was never able to set it up and get it to work for Approval/Sign-Off because it asks for Site Info, and Path names that, as hard as I tried, I could not get to work.  SharePoint and Flow and me are good friends, I had no problem setting them up, and although you have to click on the"Run Flow" tab to get them to execute,  I had no real problem.  By default fields are appropriately populated with GUIDs, Site info etc.

And if I place files in Teams and then open with SharePoint no problem.  Problem is share point gives the ability to approve using Teams, but does not update the column of "Sign-Off Status".  If you use "Sign-Off" from SharePoint the "Sign-Off Status" column is updated.  Also in Teams there is no way to display the "Sign-Off Status" column, in-fact there is no column chooser at all.  What you get is what you get and that's it.

You ask why do I want to use Teams.  Well in SharePoint you are forced to enter an email address for approval, and that is just too random.  I want to assign who is/are the approval personnel for each Team, not leave it to the creator of the Purchase Requisition. 

I really think Teams is going to be a good product, but it is in its infancy, and has a long way to go.

Is there a better way to automate sign-off on documents?