Struggling with backend development, how do you improve when it’s all internal?

I recently joined Meta as a mid-level SWE and matched with a backend-heavy infra team. I chose it because I wanted to grow. I've been forcing myself to keep doing backend because it always felt harder, and I didn’t want to keep avoiding it. I’m technically full-stack and enjoy frontend/product work more, but this org is very backend-focused, and I don't know how much product work (like internal tools) drives impact here. I'm assuming it doesn't as much as infra, because the whole org is infra.

Now that I’ve been on the team for ~2 months, I’m really struggling. I want to get better at backend, but I genuinely don’t know how to improve. Even small changes feel like editing 20 files. There’s no clear testing strategy, and things are very company-specific, so I can’t Google, build side projects, or learn in public like I could with frontend (React/HTML/JS). Backend here feels like a wall, and it’s hard to build intuition or momentum.

I’ve been reading test plans and tracing code, but it often feels like I’m guessing. I also know I need to hit "meets expectations" to transfer internally, which I understand, but it makes it feel like I have to get good at backend, whether it fits me or not. There is a possible exemption path, but I think I wouldn’t even be eligible to ask until I’m at least 6 months in, and I’m not sure if that’s worth pursuing.

So I have a few questions:

1. How do you get better at backend (infra-style, internal tools, big-company scale) when it’s hard to Google or practice on your own? I've been asking my team members, but I just feel like I can't get any straight answers from them. I even asked how I can trigger or test the code, and even for that the answer was "most of the time you can't."

2. If you’re full-stack in a backend org, is it okay to lean into frontend work for delivery — or does that limit your growth and impact?

3. Has anyone here ever successfully switched teams before the usual 12-month requirement? Is asking for an exemption ever worth it?

Appreciate any thoughts or advice — I just want to find a path where I can both grow and be effective.