Edit 1 :
If you’re fed up with companies fucking you over there’s an alternative.
There software called Nextcloud which you can run on a server which works in comparable ways as Onedrive/Google Drive/Dropbox/etc. works.
You could host it yourself on a server if you know how.
If you’re not familiar with forwarding ports or setting static IP adresses you can rent some server space from Hetzner where Nextcloud is included.
Edit 2 :
I’m totally in favor with your post, but not everyone is willing to self-host or is capable of doing it. So I recommendation would be and one that I’m currently using, is when uploading a file to these cloud services encrypt your files. I’m using #cryptomator, but I’m sure there are other alternatives, like #rclone. There is also #veracrypt, but to my understanding, is not great for cloud sync.
Cryptomator official website Quick youtube video in how to use cryptomator (3:51)
Cryptomator is open source and free, but only on desktop. To use the mobile version, you will have to pay. Here is a list of alternatives to cryptomator, if you are familiar with one, please share your knowledge.
Edit 3 :
Don’t forget Syncthing, I always suggest it first since it doesn’t require a server or advanced knowledge to work.
Your smartphone is already an always connected device, and you can manually do periodical backups on external drives which is a good practice in any case.
You can also set which device rules the file modification (sent or receive only as a folder).
I think it’s ok for most of the people. If you have a tons of precious files to save I can agree with you, but I think this type of “off-grid self-hosting” is just the future of personal data management.