This is the first time I've heard of Yunohost, but their documentation instills a lot of confidence in me.
I've been thinking of setting up NextCloud or similar for starting self-hosting of our HOA's email server, and file host, but it felt like a huge lift for someone who has never done it before.
Seeing that this is a full-on OS distro (Debian based), has been used and improved for over a decade, has docs that address backups, restores, and various attack vectors, has all app users integrated via LDAP, I feel comfortable at least giving it a try.