How flat is reasonable with a hand plane?

Sorry newbie question here. I'm working on squaring and flattening the ends and sides of small oak panels for some DIY speakers. I have an oak Japanese plane with chip breaker and I assume a 45 degree angle. I know I could probably make the bottom a lot flatter and replace the blade to get better results. But how flat can I reasonably expect to achieve with a basic hand plane? I would really like a surface with a tolerance of 0.05mm(ish) if I can. But my shavings are at least 0.17mm thick so I don't think I can get the surface I am looking for. So my questions are:
- What should my expectations be for a good, great, and best flatness?
- What are the biggest contributing factors to a plane precisely flattening a piece?
- Are there specialized planes that are meant for flatness?

Thank you in advance!