I think you’ve put more thought into how to get started than many others would! You have a pretty good plan from what it seems. My thoughts from each section below.

Hardware: I’m partial to Crucial and Kingston for storage that is affordable and dependable

OS: I’d probably spin up a Debian install if I were in your shoes and run my services using docker-compose files. It’s a quick and easy to get up and running, and despite the ease, there is still the option to do a lot of customization when you want to, and that will make it easy to learn more at your own pace and leisure.

Services: For the CalDav portion, I’m really liking Radicale.

Security: PiVPN is what I’m running on my actual RPi along with PiHole, and it was a super simple setup. I connect via Wireguard from any of my other devices.

I don’t have an answer for you, but a dev for that DigitalDiary app posted earlier today looking for feature input and saying they are going to open source it in the next 2 months or something like that. I don’t have a link to the post, sorry, but I just thought it might be helpful to know about

We do our part to keep social security solvent by working until right around the exact same time the bad dreams release us

Thanks, Obama

There’s nothing I love more than a well-explained joke