You're right, but for a counter-point versus Chromium, multi-account containers are worse for security compared with profiles…
This matters when you can't 100% trust your browser session, or the installed extensions. Did you ever load https://my.1password.com in your browser? How do you feel about it? Do you trust your installed extensions to not take a peak? I don't.
Chrome solves this elegantly via profiles. Even more, you can install websites as “apps”, with a shortcut that gets indexed by the OS, and Chrome remembers the profile. I simply type “1Password Online” or “Banking” and my Chromium opens a new window in my “Private” profile that has no extensions installed. Firefox dropped the ball on both PWA shortcuts, and on profiles.
Even for using multiple accounts, I feel like Chromium profiles are a better solution.
For example, my workplace has very strict security requirements, and when looking at company documents it's not cool to provide access to extensions like LanguageTool or Grammarly. I'd be in trouble. And Chromium always had finer grained permissions for extensions, like activating or deactivating them per website.