How do I get past the fact that im never going to be able to find
There's nothing to get past here. You need to convince yourself that "finding everything" isn't actually your role. Your goal is to help your company get to "good enough". And understanding what is "good enough" in the context of your company and your customers is the key.
I strongly recommend that you grab a copy of "Perfect Software and other illusions about testing" by Gerald Weinberg. This book is a high-level look at some of the "big picture questions" about testing, such as: Why do we have to bother testing? Do we have to test everything? What makes testing so hard? Is perfect software possible? Why can't we just accept a few bugs?
Reading this can help you understand that perfection cannot be a realistic goal.