[KevinH]

Given you are on a Mac, there really only is one internal driver for QtWebEngine anymore.
But for the record to launch Sigil with an environment variable set for testing purposes you use Terminal.app and use:

export ENVIRONMENT_VARIABLE_NAME=VALUE
cd /Applications
open ./Sigil.app

My guess is it the OpenCore Patcher you are using to run a version of MacOS that is not supported by your hardware. It constantly patches drivers for gpu/graphics.

Is there some reason you feel the need to run Sequoia via a patcher and not the latest supported Mac OS for your system?

Also If you are using any type of MacOS anti-virus checker, please disable it by rebooting into safe mode and testing.

I tried the OpenCore patcher for a few months but it generated enough issues on my old iMac that I finally gave up and just installed Linux on that machine and now that machine is running the latest version of KDE 6 Desktop, Manjaro Linux, and Sigil 2.4.0 with no issues and still getting security updates.