Could you please elaborate? I'm not sure if I get your points.
Gnome
The GNOME Project is a free and open source desktop and computing platform for open platforms like Linux that strives to be an easy and elegant way to use your computer. GNOME software is developed openly and ethically by both individual contributors and corporate partners, and is distributed under the GNU General Public License.
Sync needs algorithms (what to do with conflicts), which depend on the vendor, so built-in support for Nextcloud sync without their client installed isn't going to happen.
oAuth login for Nextcloud might, though.
I think OP wants authentication to services to happen via OAuth (or is it called something else), where you get redirected to a web interface, sign in with your Master password and grant the Gnome app access to the service. As opposed to having to create an app password in e.g. Google web interface and using that for the Gnome app
@bennypr0fane i never talked about google but nextcloud
But I can't see any mention of Nextcloud either...? I took your post to mean any of the available online accounts, as you're didn't mention one specifically. Google was just an example
@bennypr0fane it’s true i read again it seem in my edit before posting i removed nextcloud my apologies