Linker fails when linking QtWebEngine for both Intel and arm on macOS

Qt 6.5.5 builds fine if just build "x86_64" or "arm64" separately, but when building together, using,

-DCMAKE_OSX_ARCHITECTURES="x86_64;arm64"

the linker fails with

ld: B/BL out of range 153338796 (max +/-128MB) from 0x00014024 ('qWebEngineGetDomainAndRegistry(QUrl const&)'+28 from '/Users/<my name>/Qt/6.5.5/Src/build_both/qtwebengine/src/core/api/CMakeFiles/WebEngineCore.dir/qtwebenginecoreglobal.cpp.o') to 0x092503D0 ('<anon>' from 'stubs-got-file')

From a quick web search, some suggest adding "-ld64" to the linker flags, but I have no idea where to put this in the Qt Src files.

(Qt 6.5.3 was the last Qt version I was successfully able to build unified.)

I'm building on Sonoma 14.2.1 on a macBook M2 with Xcode 15.2, and it's associated command line tools.