This is exactly why I stopped using Dropbox and moved everything I have to my own https://nextcloud.com instance.
It's very easy to install and upgrade, it is stable, have way more features than Dropbox and you have total control over your own data. Overall a superior experience.
If they would do something I don't like, I would just never upgrade anymore and be done with it or just copy the files out of the /data/Nextcloud folder and move to another one open solution.