Are you looking for your first RC construction vehicle?  The Yi Gong YG636 is a mini RTR crawler loader from the 1:50 scale Alloy Engineering Vehicle series.  It can be used indoors or outdoors.  In the videos below, you can see a detailed review of the machine and a demonstration of its capabilities, including operation in real dirt/sand conditions.  I also disassemble the machine to show how it works.

https://youtu.be/Kpb95aLMrFA

https://youtu.be/nJ0ZaZq75TA