Ontology: philosophical study of the nature of being, becoming, existence, or reality, as well as the basic categories of being and their relations.
Epistemology: study of the nature and scope of knowledge and belief
I am interested in topics that is related to the questions that if the reality that we perceive is the only thing that exists, for example, could we be in a simulation? Are we just brains in a glass?
The other topics I like to know is that if knowledge is fundamentally limited. For example, any theory of science has to start either by an axiom or an empirical observation. The axioms of geometry for example cannot be proven. Do we have the capacity to understand whatever there is about Universe? or Is there a limit to understand the physical laws of Universe or Mathematics itself?
I feel these topics I mentioned are related to Ontology and Epistemology, however, I am not sure. It would be good if someone could help be to find out which branches of Philosophy I should have a look.
So my questions:
1- What branches of sub-fields of Philosophy does study the topics I mentioned?
2- What are the good book or sources about these topics or sub-fields?
3- Is there such a thing as fundamentals of Philosophy, the same way that we have in Physics and Mathematics?