> Sandstorm is basically abandoned
This is untrue. Sandstorm gets monthly releases, and new features tend to show up every couple months or so. Several major improvements to the platform are in the works at the moment. It's definitely true we could use more help, but it's still probably the most secure way to self-host cloud services for personal use.
> Cloudron is not even open source
True, though it's probably the best "successful" approach right now, in that the Cloudron devs have a functional business that allows them to very actively support the platform. (Sandstorm failed here, so as a Sandstorm contributor, I can't really knock their approach.)
> Bitnami and Yunohost are also major options.
Yunohost has zero isolation between applications, a single compromised app can hose your entire server. I would bear that in mind when recommending it widely.
Bitnami is going to leave you mostly on your own to decide how you're going to host it's app packages. I'm not sure it's directly comparable, it's more like a Docker Hub than a managed self-hosting platform.