Branching for SharePoint Dev Environment

We have six developers that produce SharePoint forms that provide data collection, workflow and front-end for MS-SQL and other databases.

On average, they produce 25 forms per month for UAT testing, and release 12 forms into production. There are two UAT releases per week, and 2 Production releases a month.

In addition, SharePoint has multiple levels in the code base - forms, lists, libraries, views, style sheets, java scripts, .DLL’s, WSP’s, etc.

I have been struggling to map any of the major workflows - Git Flow, Github Flow or Gitlab Flow - to this environment. After reading documentation, watching tens of hours of video, experimenting for several weeks - everything seems to end up in a twisted knot of branches.

How do we implement a workflow model that is manageable and understandable to our developers and administrators?