The fact that CachyOS more or less successfully replaced Manjaro’s purpose I guess is evidence of Manjaro’s issues.

I forgot but I think Bazzite had similar complaints (due to its use of silverblue) in which case it was just more straightforward to use Fedora or OpenSUSE if you don’t want to work with the read only root system.

Downstream distros need to bring additional value to the table to be worth using, otherwise there’s really no need if you can make a package group that accomplishes the same thing in one go.