The usual answer is that it depends… 
I use paperui for most items/things (except for the items where i want to use the Expire binding, which is very nice but doesn’t have support for 2.0 style items) and I use config files for rules and sitemaps. Maybe the experimental rules thingy in paperui is usable nowadays though? Somebody has to fill in there…
Have you seen the visual studio code plugin (https://community.openhab.org/t/visual-studio-code-openhab-extension/30205? It’s really nice for editing the files (instead of np++ as you’re suggesting).