Doesn’t DO itself have “apps” ?
Also see Cloudron. Not cheap but I’ve heard that people are very happy with their service. Basically you self host their “app as a service” platform so to speak.
Kind of like a super polished Sandstorm, but totally different sandboxing technologies (believe Cloudron uses Docker but not sure if they still do—- and I believe Sandstorm used Kenton Varda’s cap n proto technology which probably allowed for even greater sandboxing/protection than Docker, I would have to imagine..)..