Down to bedrock is an idiomatic expression that refers to reaching the basic or fundamental element of a situation or problem. Synonyms for this phrase could include getting to the heart of the matter, reaching the crux of the issue, or digging down to the root of the problem. Additionally, some other options might include stripping away the layers, uncovering the core, or unraveling the essence. Essentially, all of these synonyms convey the idea of peeling away extraneous details or distractions in order to focus on what is truly important and essential. Using any of these phrases can help you emphasize the importance of getting to the bottom of an issue.