You have a Flatpak package installed from the gnome remote, but you don’t have the gnome remote configured. I think this is a bug in an OS script which switches various packages from the gnome remote to flathub.
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= Flatpak remotes =
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eos-apps Endless Applications https://ostree.endlessm.com/ostree/eos-apps - 1 system
eos-runtimes Endless OS and Runtimes https://ostree.endlessm.com/ostree/eos-amd64 - 1 system
eos-sdk Endless Runtime and SDK https://ostree.endlessm.com/ostree/eos-sdk - 1 system
flathub Flathub https://dl.flathub.org/repo/ - 1 system
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= Flatpak runtimes =
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...
org.gnome.Platform/x86_64/3.28 gnome 919a927d133a ? 1,3 ГБ system
...
Мар 05 22:23:18 endless eos-updater[908]: Fetch: failed to pull necessary new flatpaks for update: Remote "gnome" not found
Мар 05 22:23:18 endless eos-updater[908]: Changing to error state: org.gtk.GDBus.UnmappedGError.Quark._g_2dio_2derror_2dquark.Code1, 1, Remote "gnome" not found
Please run the following commands:
rm -f eos-update-flatpak-repos
wget https://raw.githubusercontent.com/endlessm/eos-boot-helper/135cc5c10a1731475aa8323b576bf6beec936789/eos-update-flatpak-repos
chmod +x eos-update-flatpak-repos
sudo ./eos-update-flatpak-repos
(This fetches and runs a new version of the buggy OS script, in which I’ve tried to fix your problem.) Then collect a new eos-diagnostics file, and post it here.
Finally, try updating your system again.