> As an example, let's say I'm new to elisp and I am wondering how to insert a character to a buffer
You can use google as with any other software. If you search for 'elisp insert character' with google the first hit is the insertion section of the manual which tells you the functions:
The fact that google is your goto method shows that the discoverability is poor. I could code in JS offline for hours if needed, because all the information is there in the objects, but I would hit a wall in 5 minutes with elisp because this "object oriented" concept and console.log(anyObject) simply do not exist.
I use google when coding JS code too, because completing functions of objects for discovery is useful only in the more trivial cases. For anything non trivial using google gives much quicker results than browsing any kind of documentation.
In case of Emacs I use the manual as a reference (looking up things which I already know about) and I use google for discovery of new elisp concepts.
Helm has a lot of extensions, here are some popular ones: https://emacs-helm.github.io/helm/#helm-applications
> As an example, let's say I'm new to elisp and I am wondering how to insert a character to a buffer
You can use google as with any other software. If you search for 'elisp insert character' with google the first hit is the insertion section of the manual which tells you the functions:
https://www.gnu.org/software/emacs/manual/html_node/elisp/In...
As with any other software using google you can find things much more efficiently than with the builtin searching functions.