Thanks @AdrianS for the added feedback and thanks @BrechtSchamp for the assisting! In addition to leveraging configuration templates, you also have the option of using the Dashboard API perhaps. In general, when it comes to things like large scale deployments, or very repetitive tasks, templates can be great, but there might also be an option to do those things programatically with a simple script making API calls as it iterates through dozens or hundreds of networks in your organization.
@JeroenLicht sorry if I gave the impression that separate networks would add complexity. As @BrechtSchamp mentioned, the idea is an "Organization" of "Networks", so it's all still a single pane of glass for management. Think of a "network" as really just a configuration container. And typically a network corresponds with a physical location like a building or a campus. Think of a K12 school district, where they have a Dashboard network for each school, that is the best and common practice for a number of reasons, but still allows you to easily jump from school to school for management and configuration, as well as run summary reports across specific schools, or the entire district at the Org level. Many school districts do just that, some also leverage config templates, some leverage scripting and the API, and some still do things manually school by school which can be repetitive but still simple.