A thing that most other developers miss is that non-technical people, like (and especially) content creators, shy away from a terminal as if it were such a plague.
Some of them don't even have the mind concept of a directory tree, from a root drive to nested ones.
Therefore, if you have to `cd` to a directory and then `npm run build` it, yeah: the CMS is developer-oriented no matter what you claim. Once your Windows customer tries to run that command (assuming they know what `cmd.exe` is) they'll run into `'npm' is not recognized as an internal or external command, operable program or batch file.`. If it's a Linux person, they may find `node` and `npm` installed, but then it's closer to a developer than the pure content creator this is trying to target.
These products seriously need to compete with the 5-minute WordPress installation. I'm no WP fan, I really don't, but I give credit to its low-friction onboarding.
> Aether stores everything as Markdown files with YAML frontmatter.
Yeah, just like GravCMS[0]. Full disclosure: I'm a Grav user.
Except that Grav has a web admin interface: now, that is more approachable to a non-technical content creator than typing commands in a terminal.
I really don't want to make my comment feel like a rant, but it's very hard to ignore that some devs entirely miss the target public they intend to approach.
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[0]: https://getgrav.org/