UE 4.24.3 is stable when using only OpenGL not Vulkan. I dont have Ubuntu 18.04.5 LTS any crashing problems when im using OpenGL. And Now im installing Nvidia 470.57.02 drivers and this working very smoothly.
Next you should try to compile this 4.27.0 version. Its previous versions up to version 4.24.3 crashed when compiled. That is, the building crashed about halfway through the error messages.
I have only 8 gb memory and my swap is 2.1 gb. So far, memory and swap have been enough for building a program.