Video Production is time consuming. Even a short video can be extremely time consuming to build from scratch and the reliability of templates from third parties is sketchy at best and even more time consuming at times.
The next alternative that comes to mind is something like Spark from Adobe, and there’s a few that closely resemble this, and another service such as Canva, which has proven to be a useful and FAST prototyping design tool, particularly in the early design concept stages.
Next, and best I believe is a project template style screen animated video, minimal stock, then standardized branding for logo/intro and credits as well as titles and text throughout.
Envato elements for music, some short stock clips, then the credits/intro templates with a titles/text template, and simple screen/clip placeholders for a standard project showcase video template and/or the same setup for Products and Services.