So I have an off-the-shelf nas from synology; while I have two additional servers (ThinkServer, VPS) that are barebones running Debian/proxmox, I haven't moved away from the synology box because it's so... not "easy" but it's like bowling with the gutter guards in place. For example, if you tell the firewall "hey, block everything" it will try, fail to connect to the browser you are using, revert, and tell you. It has a nice web UI that is similar to a standard OS UI. It let's you learn and try stuff, and when things go sideways it's not an evening of combing through forums and pages of documentation. I can, I have, done the 'from the ground up' on the other two systems, but for the syno: why would I build my own box, redo effort - more effort - to get to the same outcome currently? So I will hold onto it until EoL, whenever that will be.

Not to sound like an advertisement, but it does file sharing pretty easily ootb, and you can either set up a DDNS with a subdomain of your choosing, and a list of domains owned by synology (for newbies), or you can use that DDNS system + hook it up your own domain, like MyWebsiteWhatever[.]org. Either way, you can then access your files via a browser, software for win/mac/linux, or from their mobile apps. I also use their photo solution, and have my family pics backed up straight from their phones. Every quarter I make sure that they haven't been logged out (system update / reboots seem to jostle things) and all is well. They have a system for calendar/tasks, as well as for contacts, but I personally have moved away to a direct "radicale" (software name) system, which I think is what synology uses at its core for cal/task/contacts, just adding their gui. Anything else (for my situation) gets a docker container, and this is how I learned about containers. They seem like a black box, but they are absolutely fantastic. Again, great for learning in a controlled environment.

The whole system is very hand-holding, a bit too much so at times. But coming from a "I'm a geek who wants to learn 'proper' network sharing, and this seems to be a nice solution", after researching a few popular options, I think I did well. If you can setup things like a static IP in your router, if you can port forward, and if you're willing to shell out the initial cost for the system (which is overpriced, honestly, but you're paying for the simplicity) and hard drives... you should try it. It's not as scary as it looks. Shoot, if you want more details I can dive in and explain specific stuff, examples, screenshots. Though maybe over DMs so I don't flood the post with unrelated stuff :p

E: autocorrect shenanigans

E2: more detail