How do I remove the left-side window control buttons in Mailspring on Linux?

I’m running Mailspring on Pop!_OS with the COSMIC desktop environment, and I’ve noticed that my application window displays two sets of window control buttons — the macOS-style circles (close, minimize, maximize) on the left side of the title bar, as well as the standard buttons (minimize, maximize, close) on the

right side.

I only want the right-side buttons. How can I remove or disable the left-side traffic light buttons in Mailspring?

I don’t have this issue. GNOME 49.

I have the same issue on Void Linux with Gnome 48. It started after an update a couple of weeks ago