> the configuration is very arcane at times and monolithic;
For my needs it seems quite modular. I have one ~/.mutt directory with separate muttrc files for every email account (10+) and within each account I use folder-hook to have separate (many are shared) config files.
It does get more intuitive over time once you grasp some of the fundamentals of interactions with external programmes and how the query language and hooks are what you should first reach for. This I suppose is the “arcane” part, it can be difficult to both grasp and find good resources that teach you the ropes. However, this is fairly common for the *NIX command line and can be a strength as well in the end.
What usually gets me is how some functionality is just barely out of reach, unless I am mistaken for example there is no way to pipe the path(s) (not the message(s) themselves!) to an external programme. So for my snooze script I instead pipe the messages(s), parse them to extract the Message-ID(s), pass them to Notmuch to turn them into path(s), save to a temporary file, launch another command pointed at the temporary file, query the user for input, create a directory based on the input, and move the file(s) into the directory. It works, but it is awfully roundabout and I do at times wish I had some sort of scripting language that interacted with Mutt primitives rather than a monolithic set of functions which can only be extended by patching the source.
After many years of using mutt the lack of flexibility really started to eat away at me. I decided I'd write my own console-based mail-client with a real/complete scripting language.
The result was very flexible and customizable for myself:
Unfortunately after 10+ years of self-hosting my email on a virtual machine I've now switched to paying for GSuite, so the project has become orphaned. For a while I thought there was a chance it would become popular and useful, but I guess the userbase for these kind of applications is pretty small - almost everyone still using mutt does so because they love it, and are used to it. Changing isn't an easy thing to do.
For my needs it seems quite modular. I have one ~/.mutt directory with separate muttrc files for every email account (10+) and within each account I use folder-hook to have separate (many are shared) config files.
Arcane is more subjective, but I like it.