Fri Nov 08, 2019 4:38 pm
There isn't any formal support for RetroPie on the Pi 4 just yet. You may have some luck in getting it to work using one of the online tutorials but at the moment the performance (reliability) seems to be a bit hit or miss depending a great deal on what system(s) you are trying to emulate.
I doubt many people using RetroPie will have their system doing anything else as just doing that is very hard on resources. You would probably be better off having separate Pi's for these tasks or even consider something different for the NAS as even a fairly cheap dedicated unit will probably outperform a Pi in this regard.