On Gnome, "Web".
On macOS, Safari may not pass your "non-corporate" requirement, but it's spiritually non-corporate, and functionally "just a browser". It's also wicked fast and extremely light on your resources.
On many platforms, "ungoogled-chromium" may satisfy your needs. It's under the name "eloston-chromium" in many repos. https://github.com/ungoogled-software/ungoogled-chromium
https://html5test.com/results/desktop.html
Looks like its the worst. Unless you have something proving otherwise. Till then I'll assume all your facts are bullshit.