For C++, I use clangd (works fine for GCC projects). The only config it needs is the path to compile_commands.json, which can be automatically generated by CMake and some other build systems. For TypeScript no config is needed. For Java there is the redhad Java plugin in VS which provides good indexing.

Not using VSCode currently but I think pretty much yes.

You can goto or peek definition in VSCode. And the find tool has the option to find all occurrences throughout your project.