I think digging into the code for 2 hours solo is very important. If you still can't find it, ask a senior dev. Actually being familiar with the code is important to be able to nail down how things work abstractly to the actual implementation. Code is the ultimate source of truth. You are going to reach a point where you come to code written by an engineer who has left and nobody else understands. You will also need to dig into an open source project at some point without any help.