Lots of companies sell Android devices without explicitly calling it Android. The most notable example is Amazon (Android - without GApps - is the OS on pretty much everything in the Fire line, e.g. Fire Tab and Fire TV).

In other words, I think you've got it backwards: you're not allowed to use Google's branding/trademarks (including "Android") unless you have authorization from Google. Meanwhile, I'm not aware of any requirement to call the OS "Android" even with that authorization; the word "Android" doesn't show up at all in the official product page for Samsung's Galaxy S9 [0].

[0]: https://www.samsung.com/us/mobile/phones/galaxy-s/galaxy-s9-...