Sunshine needs a Wayland compositor to capture from. Gamescope already owns the physical display. They can’t share it, and the workaround I’d been running — disabling Sunshine at boot — isn’t a real solution.
The actual fix: a second Wayland server, running headless.
gnome-shell --wayland --no-x11 --headless \
--virtual-monitor 2560x1440@60 \
--wayland-display wayland-headlessThis exposes a socket at /run/user/1000/wayland-headless that Sunshine can target. Gamescope keeps the physical display entirely to itself. No contention, no boot flicker.
Mutter 49.3 (Fedora 43 / bazzite) handles the headless virtual monitor without complaint, including on NVIDIA 595.58.03 — which I wasn’t confident about going in. Idle memory lands around 230–300 MB.
The service lives in a systemd user unit, backed by a launcher script in the bazzite IaC repo so it survives reinstalls.
One thing that caught me: just capture-services only snapshots top-level *.service and *.timer files. It skips drop-in directories entirely. Sunshine has an override under sunshine.service.d/ that sets the Wayland display target. That override wasn’t getting captured, so the repo looked complete and wasn’t.
The service is running manually for now, pending an end-to-end Sunshine → Moonlight test. Once that verifies, it goes in as a proper boot-time dependency.