The best way i have found to install on Linux is to use Achetas Epic Asset Manager.
There is also a Git, but that is the authors preferred distribution method.
This downloads and installs the official engine/image. (I do not full understand how this works)
Credit to Adam Rehn for working out that part. (adamrehn (Adam Rehn) · GitHub)
This, in the end, takes about 1/10th the space of build from source code.
https://github.com/orgs/epicgames/packages/container/package/unreal-engine