Always happy to welcome more people in the community!
The first task would be to build and successfully run the entire LLDB testsuite in your environment 
Potentially a good beginner issue could be more patches in the line of Change GetChildCompilerTypeAtIndex to return Expected (NFC) by adrian-prantl 路 Pull Request #92979 路 llvm/llvm-project 路 GitHub.
We have lots of APIs in LLDB that return a result and take an Status object by reference, and it would be highly beneficial to convert these over to llvm::Expected, which forces us to check the error at the call site. These are pretty straightforward refactorings, but it needs some thinking about how to appropriately handle the errors in each case. For example ValueObject::AddressOf() has only a handful of uses, so it could be a good first patch to discuss.