I think whether you do closed source software is a personal choice. Based on considerations of your application. Like money, of if you want to rely on a company and how well they do their job, if it’s still gonna be around in 7 years. If you can customize it enough to suit your needs. Or you base the decision on ideology.

I’ve been using Yunohost on the NAS. And it’s simple, works well and is pretty reliable, I didn’t get any major issues for many years now.

Downsides as a proficient Linux user are: You can’t just mess with the config while the automatic scripts also mess with the config. You need to learn how they’re set up and work around that. Hope software has a config.d or overrides directory and put your customizations there. Or something will get messed up eventually. And you can’t just change arbitrary things. The mailserver or SSO and a few components are tightly integrated and you’re never gonna be able to switch from postfix to stalwart or something like that. Or retrofit a more modern authentication solution. It is a limiting factor. And YunoHost doesn’t do containers, so I doubt it’s what you’re looking for anyway.