Godot does have support to compile to iOS on Linux with DarlingHQ?
DarlingHQ is a WineHQ clone but for MacOSX and it can run XCode without GUI
Cross-compiling iOS export templates from Linux doesn't require a full Darling installation, only darling-dmg. See Cross-compiling for iOS from Linux.
However, the documentation may be out of date as this method is rarely used in production.