VoxeLibre is designed to be very similar to Minecraft without needing to tinker with mods or settings so I would definitely suggest starting there
That said we've ran several different Minetest worlds and our other favorite was Asuna with additional mods
Thank you; it's been a long, hard road for sure and our kiddos are now grown and doing well. We took the lessons learned and went into foster / adoption and now have a large family which has been a huge learning experience of its own.