Historically, people used :grep and the quicklist to jump between project files based on abitrary strings and Ctags to generate a language specific index of functions, variables which you can jump to.

These days people generally use some kind of fuzzy finder plugin thats basically the same as the vscode experience. Exactly which one you use depends on various factors, but Telescope and Fzf are two big names and both allow searching through a bunch of other stuff, setting names, edit history etc. (You can also save the fuzzy search results to the quicklist so you've basically got a reusable index).

And neovim is heavily embracing the LSP paradigm, where you'd use something like gd to jump to definition when on top of a function and a language specific LSP server will tell Neovim where to jump to.