Project Map takes too long to save

Can someone help me with the map that I am using. It takes over 20 minutes to save or autosave my map. It is a demo map from a pack I bought on the marketplace. It happens with any map that has a lot in it. How can i reduce the time it takes to save a map?

Yes, a huge landscape. I am trying to make an open world type map. I am using an external usb. Although its the same when i put it on my computer as well.

Thanks for your help

Thanks for your help so far, i will look into level streaming. What do you mean you gave up on UE Landscapes? You mean you make your own now? The landscape i am trying to use is from a demo project. It has a lot of mountains so it’s not just a flat ground. But i do think it’s a good idea to just replace it with a regular floor for Dev purposes now and bring in the landscape later. I just hope I don’t have any problems because the landscape I want to use is uneven.