Yes, I've created single-file Gleam executables by compiling to JavaScript and then using Node's experimental SEA (single executable application) feature. As a bonus, typically I've found the JavaScript targets to run a good deal faster for number-crunching tasks.
How big is a hello world executable in that case?
Hefty. The process is effectively just injecting all of the JS into the Node interpreter executable, so it's the size of the interpreter plus whatever you stuff inside. It's close to 50MB.
Oof, well that’s not ideal.