This is my impression - if you explicitly don't want to use toolbox or devcontainers I don't think you're on Bluefin's happy path at all, and the maintainers don't seem concerned enough by that to improve other experiences.
No but Bazzite DX is almost done so we can start working on Bazzite GDX soon, which is going to be our game dev image. Though hopefully as more things become flatpak native ideally someday the idea of specialized images won't be so necessary.