There is a bug in GTK3 which will never be fixed and stops applications like Totem, Epiphany to use hardware acceleration. There is a simple workaround though: `export GDK_GL=gles`. This should be added to these tweaks to provide a better out of the box experience. Taken from the [Purism workaround](https://source.puri.sm/Librem5/librem5-base/-/merge_requests/158).