applications – Designing android apps: Material design and apps with own character

I’m new to mobile app development. I came across material design and its guidelines even though I just scratched the surface. I basically am curious how strict the guidelines have to be followed to be still considered material design and if there is room for individualizing the design for example with own components but also generally giving the app its own character.

I also wonder if one should keep consistent designs across platforms like for example when also developing an iPhone app which has own components and guidelines I guess. Or also responsive web apps where one has more freedom to design.

I’m looking forward to hear your opinions on this topic and also would appreciate if you share anything that brings me further or gives me food for thought.