I'm actually having the exact same issue as you. It is definitely a big problem seeing how RetroPie has very useful settings where as RecalBox doesn't. It was nice that one could launch a game and then change settings for those games such as resolution. With RecalBox I have yet to find out how to change resolution for specific games. I only know how to change resolution for the platform in the recalbox.conf. There are so much more guides online with RetroPie. Even the forums are better at helping it seems. I really do feel you pain.