Should we create our own framework or go for open source like Material Design?

I work in a small company that is into software intelligence. I am struggling to convince them to bring consistency in their products by having their own front end framework. Some of the key leaders are fine with Material Design considering the budget, resources and time. Some are not. They want to build their own framework but in minimum time, with fewer resources, and making the reusable components.

Which technology should we use if we go with the 2nd option (Creating our own framework). They are afraid of investing more time and which in turn would affect the business. On the other hand, they want to create a visual signature as well.

What another open source framework we can use apart from Material Design? Some people suggested Bootstrap, where you can use your favorite components to design the front end. Isn’t it like building your own library in terms of time, resources. Would it be a reusable component and easy to maintain?