Well, the one thing I did not found while investigating this, was clear information.
It seems most of this is work in progress and not really a high priority as people with a discrete GPU in a laptop are a minority.
I assume the browser could request the GPU, because my normal games also can. But the only way to get chrome and firefox use the real GPU, was an explicit setting somewhat hidden in the windows UI.
And as a standard this might sense, as my GPU really draws battery and gets loud, which I do not want for random websites. But for some websites/apps I would grant that permission. But consensus seems to be that users cannot be burdened with even more permission dialogs, so here we are.
