Epiphany (Gnome Web) requires mesa-gles to work correctly
Epiphany requires mesa-gles (specifically libGLESv2.so.2) to work correctly, otherwise while the application will start no page can be rendered.
The logs will be full of these:
(epiphany:17327): epiphany-WARNING **: 11:57:48.458: Processo Web falhou fatalmente Couldn't open libGLESv2.so.2: Error loading shared library libGLESv2.so.2: Ficheiro ou diretório inexistente
Simply installing mesa-gles fixes the issue and allows it to work correctly.