on Ubuntu / Linux Mint there's a PPA with VA-API patched Chromium builds.

So Chromium users have had hardware acceleration on Linux for some time, depending on their Linux distribution or if they installed the patched Chromium in some other way. It's worth noting that Chromium web browser had patches that allowed making hardware accelerated video decoding available on Linux for some time, and some Linux distributions packaged it using those patches. Using hardware-accelerated video decode in your web browser should result in using less CPU usage (and thus, less battery draining) when playing online videos. This article explains how to enable hardware-accelerated video decoding in Google Chrome, Brave, Vivaldi and Opera web browsers running on Debian, Ubuntu, Pop!_OS or Linux Mint (Xorg only). Google Chrome is not the only Chromium-based web browser to support hardware acceleration on Linux though.

Google Chrome 88 (and newer) has made hardware accelerated video decoding available on Linux, but it's not enabled by default.

Ubuntu edge browser