Well here’s the thing, either you get the clay that you can use forever or the one that you can heat up and let it be. Their are nuisances to both options, either for the ones you heat up there is a chance that it will have cracks but it will be the same forever. The second is you use plasilina (for Mexico) which can make literally anything but it will droop eventually. Here is the link for one version
My sister has made intricate models out of this stuff. Be warned this stuff doesn’t really work very well with carpet.