Why have you never been able to do it? I set up a full mail system years ago on a Xen/Linux VPS with stuff like Postfix, maildrop, Courier IMAP, a custom set of MySQL tables for aliases and such, and at one point migrated my TLS from CACert to LetsEncrypt. I enjoyed some aspects of the huge pain in the ass that all of that was, and having it work nicely was great. Spinning up a new email alias was easy and free, so I created a new one for damn near every site I interacted with, which later turned into a form of lock in having to continue running my server.
The continual server maintenance was a pain in the ass, requiring me to remember in substantial detail how it all worked so that I could appropriately integrate new things I had to learn like SPF and DMARC. I’m glad to have had some detailed sysadmin experience, but I was so glad in the end to finally migrate away from all that and just pay Fastmail instead.
I still have nearly the same flexibility with Fastmail and my custom domains, but they’re the ones that need to do all the maintenance. I can’t scale across unlimited domains for the same zero marginal cost, but I can make it work for a reasonable price with a few domains and scale arbitrarily within that. I’m sure there are other hosts out there that do a similarly good job, and Fastmail hasn’t been without its own troubles, but it’s been a net win for me.
I don’t recommend running your own server. I won’t do it again. I do recommend building an army of custom aliases all at your own custom domain(s).
Second this, including buying from Costco. I don’t love the Lorex interface, but they’ve been around for a long time and can’t really compete on the modem Ring-style features so they’re now advertising the privacy benefits of their local storage.
PoE (Power over Ethernet) cameras are the way to go, connecting the camera wires directly to the NVR box, which doesn’t itself need to be connected to your network. The NVR box has a hard drive and an HDMI port. If you do optionally connect it to the network (but just don’t), then their app will facilitate connecting to your box either locally or over the internet so that you can stream your video directly from your hard drive, not their cloud.
If you want it protected against power outages, you just put the NVR on a UPS and you’re done.
Of course, if a burglar finds your NVR and takes it, then all of your footage is gone.