Feeling lost as developer in blockchain company

I've recently started working at a blockchain company, and to be honest, I’m finding it quite challenging. With over 8 years of experience as a developer and more than 5 years working with Rust, I assume that's why they hired me. However, before joining three months ago, I had almost no knowledge of blockchain. I've picked up quite a bit since then, but the codebase still feels like a mystery. The documentation is scant, the code is often tangled, and the extensive use of macros makes it tough to follow. It appears much of the code was written in a spontaneous manner, without much forethought. While the engineering team is undoubtedly talented and skilled, there doesn't seem to be a unified plan. I’m regularly asked to review code, but without the team's shared knowledge, the reasons behind the changes often escape me. I worry about making mistakes. I can only focus on reviewing the existing code for about two hours a day before my eyes start to ache, so I’ve been dedicating the rest of my time to a personal side project. I’m beginning to feel guilty for not contributing more effectively right now.