It's a nice guide. Good work. But I have a question: Why would a noob do all this on a dedicated machine just to connect Sparrow?

You can run a bitcoin node on any PC with any OS, without Electrs anf not even needed to be a full node connected 24/7. You can run it only when you needed and connect Sparrow directly.

I think these bundle nodes are pushed too hard into noobs mind for nothing. I am not saying that Start9 is not good, but for this use case is not necessary.