If you really want to power optimize, there's a special dmabuf-wayland backend that hands off compositing to Wayland. You lose some post-processing but your power use can drop from 12-15w to 2-5w. This is also how the newer Linux video players attain really low power draws.

Bonus discovery I just learned. Under nvtop -> F2 -> Processes -> Fields -> there you can make it show encode/decode. It's disabled by default