Back in the day when people wanted to share something with the world they would set up a website (instead of sharing on social media, because there were no social media). When large files needed to be moved between people, Bittorrent was used (instead of CDNs, because there were no CDNs).
These still work and needs to be rediscovered and used. Perfection is reached when torrent downloads are integrated into the browser itself.
I think the main requirement for general purpose computing is the decoupling of software from hardware and allowing modularity.
The problem is that with Apple, Samsung, etc fully integrate the hardware and software in house, this means all the drivers and blobs can be kept in house secret.
On the other hand a PC can be built by anyone from hardware components they choose. In order to make this work all the drivers and blobs for all the hardware components need to be public, and therefore can be integrated into the Linux kernel, allowing anyone to use an open source OS on their system.
Incoming mail: my own server and my own domain (Postfix). Sufficient to receive confirmation mails and notifications.
Outgoing mail: no good/reliable solution yet. I have to send personal e-mail very very rarely.
Calendar: Tasks.org app, used offline (not synced).
Drive: 1TB external HDDs. GPG encrypted backups of important stuff are uploaded regularly to one of the VPSes I have.
VPN: Tor
Password manager: KeepassXC (with backups at 3 places).
Documents: Stored on computer, important ones are backed up. Confidential ones are stored on an encrypted LUKS volume which I only mount when I need something.
In general things I need on the go (e.g Calendar) is on my phone, the rest is at home at my computer. If I need to move data between devices I simply use USB drives. I don’t need no cloud sync of anything.
I think people should rediscover the beauty of doing things offline on a computer.
I had a recent experience traveling on a train. A mother used YouTube to entertain her young kid with some children video. Every time there was an internet hiccup and the video stopped, the kid started crying…
You don’t need a NAS and a streaming media server or anything in cloud to watch your favorite media, or to listen to your favorite music. You can simply put them on a pen drive and whenever you need the media, plug it in and watch/listen offline. Using an OTG adapter you can even plug it into your phone (at least for the duration of the the time while copy the needed files off it). Most people don’t need much more than this. And if that mother put the videos on the phone before the journey the kid would never cry.
If you need a file server, you can use a basic Linux installation and enable SSH. Then you can transfer files over SSH using Filezilla or other SFTP client. For versioning you can use Git (it’s not just for programming), and the remote is just a directory on that Linux server where you have previously created a bare git repo.