We use modebug.lua (you’ll find it in builtins), but I’m sure there are others.
And if it’s anything like python, you can start the debugger server inside your program, probably with a localhost and a certain port, and then connect from it from the debugger.
A quick search found this for instance. I haven’t played with it, but it should surely be possible for you to find something that works.
https://marketplace.visualstudio.com/items?itemName=devCAT.lua-debug