If you're looking for a VS Code extension or a GitHub app, check out https://semanticdiff.com/. I'm a co-founder of this project.

If you prefer a CLI tool, check out https://github.com/Wilfred/difftastic. It supports more languages, but doesn't recognize when code has been replaced by an equivalent version ("invariances"). So it will show some changes (e.g. replacing a character in a string with an escape sequence) even though they are technically equivalent.