Greasy Fork is available in English.
Transformez les commentaires et les listes en onglets pour les vidéos YouTube
< Commentaires sur Tabview Youtube
try to disable all other extensions and userscripts
I did tested without scripts and extensions before this, but it's working fine now, it probably was something youtube related.
The player is kinda zoomed and a bit cut and the like/dislike buttons are gone unless i put it on fullscreen with f11, i don't know if it affects only my resolution which is ultrawide.