You are not done one the config is written: A configuration requires maintenance effort: New plugins get released, others stop getting developed, APIs change. You constantly need to adapt your configuration.

That is why I recommend using a distribution like astonvim. A distribution takes care of keeping the basics going and gives a well msintained base and thus gives you more time to fiddle with the interesting bits of the configuration.

Astronvim in particular is "just" a lazy nvim config and very easy to customize, filtering the standard override process defined by the lazy plugin manager.

I actually got rid of most custom config I had on top of astronvim by using its community repository: It contains easy to add config snippets that fully integrate other plugins with all the plugins in the astronvim config (lsp setup, treesitter, snippets, completion, ...). This ranges from adding one plugin to entire language packs with all the recommended bells and whistles to work with some programming language.