Limit cpu cores at make

The readme for UE5 decribes how to compile the editor. As I have 32 cpu cores the make process utilizes all of the 32 cores, which I dont want because of memory concerns.

How can I limit the compiling to a given number of cpu cores, as I usually do it like so:

make -j20

I just found out the make process automatically determines the maximum number of used cores by analysing my available free ram.