Can't generate updated world partition minimaps?

So I’m learning about Unreal Engine and testing out some things in a test project. Literally just a blank project that I just created. I started with creating a new level and choosing open world and deleting the landscape partitions and the landscape itself before importing a brand new height map as a landscape… After doing that, it doesn’t let me generate an updated minimap. It’ll just freeze or load the old minimap, which doesn’t make any sense to me? how do we generate a new minimap?