I apologise if this has been asked already but recently I've been trying to start games like Resonance, Blackwell and Gemini Rue but keep getting hit with

"Do you want the application “WineskinX11” to accept incoming network connections?"

Then nothing happens. I am playing on a Mac that is updated to Mojave. Is this a consequence of the OS upgrade?

The ...accept incoming connections pop up is just the OS firewall, it shouldn't influence the wrappers ability to run, in general. Should be fine to allow it though.

Not sure, as I haven't seen this problem personally, but apparently there was or is a bug with certain Wineskin versions on Mojave and High Sierra.

Right click the game and view package contents, look for an app called Wineskin. Its a bit buried with the way GOG sets up the wrappers. Start it and a small window should open. Try messing around with the screen options, supposedly disabling the auto-detect GPU for direct 3D setting helps to get many wrappers running.

Cant do harm to update the wrapper too (under Tool settings, just in case they are outdated)