I tried just this moment the Sunshine version from our Solus Software Center. And man, the the first launch was very strange. When I clicked on Sunshine it opens: Sunshine (yay) but also Steam, Heroic Launcher, KeePassXC, Onboard (Keyboard) and activates also the voice assistant.

After a reboot, cause it didn't know how to deactivate the annoying voice assistant, I launched sunshine via terminal, everything acts as it should be.

Checked with alacarte (menu manager) the launch command and I found my problem:
/usr/bin/env systemctl start --u sunshine

    Phiqu When I clicked on Sunshine it opens: Sunshine (yay) but also Steam, Heroic Launcher, KeePassXC, Onboard (Keyboard) and activates also the voice assistant.

    That was weird 😆

    Phiqu /usr/bin/env systemctl start --u sunshine

    I haven't tested this yet, but I don't think that launch command is the only cause. AFAIK, all it does is starting a systemd service file for sunshine. None of it saying "autostart everything".

        a month later

        Still seems to be an issue. Launching from the terminal seems to work fine for the time being but would really like to see this fixed.

        This happens because the systemd user service for sunshine specifies that it wants xdg-desktop-autostart.target which is the systemd target that starts all applications that are set to autostart (which includes user-specified autolaunch programs as well as ones that are configured to autolaunch by default by Solus packages). On Plasma at least which integrates with systemd for launching sessions this target is handled already, and so launching sunshine doesn't do anything besides launch sunshine since the autostart target is already active. On DEs that handle launching autostart programs themselves or don't do that the result might be double-launching of said applications, or the launch of the applications in the first place if something was broken about how the DE was handling it (note that it should be launching the applications and the fact that it isn't is a bug).

        This is (probably) not a Solus bug, and is an issue that should be reported to the DE issue trackers or the sunshine repo itself if you have feedback on whether or not sunshine should be doing that.