For document editing, I have had fairly good luck with OnlyOffice, although it is not without its issues. Others also recommend Collabora, which plays well with NextCloud and LibreOffice.

DAVx5 basically acts as the connector between your server and your calendar/contacts/files apps. I would imagine that this could be built into an app, but there are a lot of ways that such apps can sync or operate locally. I’m guessing that it is just a little more specialized than most developers want to get.

Thanks for the Syncthing-Fork tip! For now the official version is working for me, but I’ll have to migrate myself soon.

From my understanding, OpenVPN provides the same secure remote access as Tailscale, by a slightly different method. You should be fine to use what you’ve already set up.

I’ve done this.

For contacts, calendar, and files, I use OwnCloud, although NextCloud is as good/better. I couldn’t figure out Self-Signing certificates, which is supposed to be pretty easy, but I am kind of a dummy. NextCloud requires it. On my phone, I use DAVx5, and I replaced the GrapheneOS stock apps with Fossify apps as needed - although that is up to personal preference.

For photos, I use Immich, which is hands-down the best option.

NextCloud also has options for document editing, photo backup, and notes, but I can’t testify to those.

Syncthing is an ideal way to seamlessly sync files and folders between devices, but you will end up with the files on both devices. I use it sparingly, and they are phasing out android support. It’s still very useful to migrate large file libraries and act as a stopgap for other services.

There are tons of notes apps, and it largely comes down to preference. I settled on NotallyX, which can import your Keep notes directly (using Google Takeout iirc). It also has the option to store files externally, which means they can be synced for backup. There are also self-hosted web-apps, like Memos, or the slightly more adventurous Blinko.

I got a lot of great input from this community not too long ago.

The one Google feature I am not able to reproduce is Google Messages. If you use texting to any degree, there are some FOSS apps with pretty nice basic features (I’m using Fossify which is nice). However, there are none that have solid group-messaging features, reactions, and other RCS capabilities. It seems to be a technical/logistical/legal hurdle that is presently insurmountable. Lots of people don’t use texting anyway, so it may not be a concern for you.

Edit: And of course, you need a way to tie everything together. I use Tailscale, which is ridiculously easy to self-host.

From what I gather, most people use a simple Linux distro like Ubuntu or Debian with a large community knowledge base. Then run the pieces you want through Docker. It’s pretty simple once you learn how.

Your laptop will be perfectly capable.

Unrelated but there are several open source podcast aapps that will do this like AntennaPod or Cardo