Modern Emacs configurations tend to revolve around use-package, which wraps up the package installer logic at the end of this configuration and makes it somewhat declarative. Just going by the standards of r/emacs or places like that, it'd be unusual to see a .emacs that didn't ultimately boil down to a bunch of use-package clauses configuring stuff like LSP, Magit, company, ivy, and yasnippet.
If I was going to add just one thing to this starter configuration, it'd be a single example of use-package, to make it clear how to add and configure a package the user just read about online --- it's just such a big part of how Emacs is used now.