I think syncing kilobytes costs next to nothing and if they can't manage it then let me put in my own URL and I'll host it myself.

(And "my own URL" realistically includes Google and Dropbox and OneDrive and iCloud, not just nerd stuff. And even without automatic backups it should hold on to everything and give me an export button.)

I sorta assumed they were making money from selling you the device.

We are not required to permit every possible business model to exist. Companies are desperately trying to get their hands on every piece of data they can get to train AI, hence the abominable use of "opt out", which is already horrible even without the added bait-and-switch coercion of "or we'll make the device you already purchased worse".

"pay or consent" stunts have already been ruled illegal under the GDPR. This goes even further than that, where you don't even have the option to pay.