I find it hard to achieve true understanding reading theoretic computer science books. In particular, I struggle with symbolic notations and proofs. After spending a very long time perusing all the pages, I find that I still struggle with the very basic concepts when doing exercise problems. What's a good process to really understand the concepts being communicated in the books?
I have the same problem. I struggle with the symbols, and that makes it really hard to follow the theorems.
Recently I came across a statistics book at a library which had a list of those symbols and their meaning at the start of the book and while reading I realized something that was so obvious - I should've compiled a similar list and kept it next to me when reading a TCS text. Whenever I come across a symbol I don't recognize/understand, just look it up.
You don't state what level of TCS problems you're dealing with or what books you're reading.
There are several incredibly bad textbooks in the field of TCS. Maybe you should look for alternatives which may provide better intuitive explanations, rather than just symbolic proofs. Or maybe you should back down for a while and go back to studying the basics if you haven't grasped them yet.