Running your own email server is easy.
Getting your email accepted by other servers is hard.
Hosting anything publicly requires a significant amount of hardening.
Neither of those two tasks are easy or low maintenance. I self host almost everything and I’ve run my own mail server (with occasional rejection). It’s not worth it for me; I now use a commercial, paid provider for email.
Myeah but it’s just a server - the clients just use Matrix.
Plex has clients for every single device there is. I arrive to some 2018 smart tv in a holiday cottage and the absolutely dreadful, measly App Store, now long abandoned, has a plex client.
Also I have a very old life time pass so current pricing means nothing to me.
I run Nextcloud all-in-one containers and I literally have to do nothing, ever, to manage it.
Whatever you end up buying, and I speak from bitter experience here, swap the SSD that it comes with it. Consumer SSDs in micro systems do NOT have the write cycles required for 24/7 docker activity.
Now I run a couple of Micron 7450 Max server SSDs. Live and learn.