This is the key. There is excellent content on YouTube, but we don't let them watch by themselves and have explained the risks of algorithms to the older two ch

This is the key. There is excellent content on YouTube, but we don't let them watch by themselves and have explained the risks of algorithms to the older two children. There's loads of stuff that is entertaining for children and parents watching together - Mark Rober, craft videos, draw-along channels, cabin building, hobby farming, streetfood, etc. Usually I will pre-vet a video myself or get a feel for the style of a channel to decide whether it's reliable or not.