I use Google Meet on Firefox on Linux, and haven't noticed any excessive power use; and the laptop fan stays slow.
In fact, of the video conference systems I have used at work, Google Meet is the only one that works perfectly on Firefox, without having to use Chromium or even a dedicated flatpak package.
In fact, of the video conference systems I have used at work, Google Meet is the only one that works perfectly on Firefox, without having to use Chromium or even a dedicated flatpak package.