Actually it's worse. They were told by the UK that they need to provide a backdoor globally.
And yeah, I'd say that's a pretty safe assumption. Especially since we only know about the Apple one because of an internal leak, with neither Apple nor the government willing to comment,
They "say" they don't feed it to AI. But Dropbox is bleeding money since 2018 and at some point, will be sold to the highest bidder and from that point, you might as well just store your data on somebody's random website.