Oooh, something I can actually help with because of direct experience!
Background 1: I lived in Morocco for a while. Background 2: we recently went on holiday to Vietnam with two young kids, and are not normally sitting-by-the-pool types.
Morocco is a fantastic country with a million things to see and do. Many of these things are not particularly easy to get to, and the most practical way to travel is in ancient and overloaded taxis. I’m not sure I’d want to do that with kids, but YMMV. So I’d say you’re best to stay relatively close to your resort. Is it in Marrakech? If so, you’re sorted. The old town can be pretty intense, but you can spend days exploring. The markets are great, and there’s lots of interesting stuff for a kid to look at. There are also some fab museums, which my kids would think were some kind of fairyland.
That said, on our recent holiday we spent most of the time at the pool because the kids had such a great time there. We limited ourselves to a few “cultural” days, with plenty of downtime in between (this is the key, I think). I think you have to cut your cloth and limit the more challenging activities. There will be plenty of time to re-balance that in future!