I've just started to use social.vivaldi.net and the the three columns fill my 1920x1080 screen.
Perhaps one day all instances will do this.
https://preview.redd.it/yf9z24mn7rzb1.png?width=1920&format=png&auto=webp&s=8916ff2d6aab6f748251dd42c9a8a72470cac2b5
