Technically, Chromium is not a version of Chrome. Chrome is a proprietary browser created by Google. Chromium is an open source browser created and maintained by Google.

Chromium alone is missing a lot of features (even more so if going the ungoogled route). Its not recommended to run standalone, although it will. Best bet of you want a Chromium-based browser is to find a forked version of it. Brave is one that comes to find, as its geared to be better for privacy.

Firefox is also a solid, secure browser. It is backed by Mozilla, which has been a champion of the open source community for years. It’s going to have a different approach to the web since its not backed by an advertising company. The default settings could be better, but I wouldn’t say they’re insecure.