changing default speed doesn't work

Ghost module that absolutely does not work.
There is no need to waste time writing these modules if the result obtained is zero.
Someone will have to explain to me where the recommendation of this module comes from, I have trouble understanding.
I remove it and we will not talk about it anymore.
Linux MAGEIA 9.0
FF 115.13.0esr 64 bits

It's great extension! At least my YouTube always run on 1080p.

Doesn't do anything on firefox mobile on android.

Does not work at all, Why still recommended?

Set to 1080p, but playing at 720
(URL: https://www.youtube.com/watch?v=tnu571p2CCw)

See here for the only addon working:
https://addons.mozilla.org/de/firefox/addon/hd-quality-toggle-for-youtube/

Não funciona

Doesn't work

ta

Does not work with embedded videos.