Users report that their Chromium account profile is deleted from Chromium during a recent upgrade to version 87.0.4280.66. During the upgrade, the user is presented with a popup box stating that their "Profile will be deleted". Once deleted, the Chromium browser defaults back to a fresh new user profile losing all bookmarks, saved passwords, and other saved settings. The option to log back into the account profile, and its sync, disappear from Chromium.
The Bad News:
This is not a bug. Per Google, as of mid-March 2021, all versions of Chromium, even older versions of Chromium, will lose access to Google API keys. This breaks features such as the Google Account Sync. This behavior is intentional and will not be corrected. In fact, additional functionality could be removed in the future.
The Good News:
Your synced account data is still available on the cloud. Note that you will lose any browser history or setting changes that have occurred since after your last sync. The work around is to install the official Google Chrome browser which maintains the ability to sync your account profile.
The official Google Chrome browser is supported in both Windows and Linux (Debian/Ubuntu and Fedora/openSUSE). You can download the official Google Chrome browser from https://www.google.com/chrome/.