The extra info in your original bug report says that your install was originally with Ubuntu 20.04 LTS but there is no upgrade log for upgrading to Ubuntu 24.04 LTS which I think means that you did not use update-manager or do-release-upgrade to do the upgrade.
I don't know if that affects how gnome-online-accounts is working for you. I was able to add my Google account to GNOME Online Accounts successfully and it shows up in my Nautilus file browser in the left sidebar in the second section from the top (listed after Trash).
The extra info in your original bug report says that your install was originally with Ubuntu 20.04 LTS but there is no upgrade log for upgrading to Ubuntu 24.04 LTS which I think means that you did not use update-manager or do-release-upgrade to do the upgrade.
I don't know if that affects how gnome-online- accounts is working for you. I was able to add my Google account to GNOME Online Accounts successfully and it shows up in my Nautilus file browser in the left sidebar in the second section from the top (listed after Trash).