If you have less than 2 years of experience as a software developer you should try to read every PR your team opens and leave a comment. Sounds like a lot of work and it is. However, you will benefit immensely from it.
Every time I sat down with a junior dev to ask why they weren't participating in code reviews they told me they didn't feel comfortable commenting …yet. It was always something along the lines of "I'm not good enough" or "I'm not familiar with this part of the code." They didn't understand this thing, they didn't understand why that change, or <insert reason here.> Maybe they'd start contributing in a year or two. You know, eventually one day.
I heard the insecurity and/or humility in their reasoning but reminded them, part of their job was to learn quickly so they could understand. The fastest way to get “there” was to read and ask questions. They didn't need to leave helpful comments, approve the PR by clicking "accept," or even find an issue. What they needed to do was make sure they were getting on-the-job education which would help us grow them into the next place in their career.
So you need to not be that person who hides away from show casing how junior you are. We all know you are Jr. We need to see where you are struggling, what concepts you still need to learn, and what things you need to be exposed to. Reviewing PRs or just code reading of PRs are a great way to help us help you.