Any idea what kind of effort it would take to get Jakt working on another OS?
Even though it doesn't require SerenityOS, even SerenityOS GUI apps can be ported to run on Linux, Andreas already has ported its Ladybird Browser that wraps SerenityOS LibWeb engine in a QT App [2] to Linux, his last video shows "Abstracting the event loop so Ladybird can be fast & responsive on Linux" [3]
[1] https://github.com/SerenityOS/jakt#usage