If you’re looking for a straightforward BP-friendly solution, I’ll have to disappoint you - there’s no support for this in base UE.
If you’re willing to do some engineering in C++, I’d highly recommend making a custom landscape solution using procedural meshes instead of the built-in landscape, because modifying the built-in landscape to support runtime modifications you’d need for a game like this is not really a one-person job because the system is quite big, messy, and rigid.
If you’re not looking for a C++ solution, your best bet is trying out one of the several marketplace plugins that mention “runtime landscape editing”, where someone did the bulk of the work for you, but it may not fit your use case perfectly and you can’t adjust the functionality without C++.