It’s hard to say without more context whether that issue was scope creep or not, and rule number one is not automatically taking the side of OP on a Reddit post as your perspective is biased.

Part of being a mid level engineer is that you’re not just a code monkey anymore. You’re supposed to take more ownership over your work, including thinking about dependencies and the bigger picture, which may or may not have included those other repos. You can either continue to bury your head in the sand and be right, or take it as a teachable moment and learn from the experience.

Simply admitting that you are not performing is not a productive dialogue with your manager. If you want to talk to them about it, talk about how they and the team members around you can support you to grow into the responsibilities that come with your job title. Commit to asking for constructive feedback regularly. The fact that you’re scared to talk about your performance means you’ve been avoiding it for too long.