Yes I had found QTWebEngine is on GitHub and all 5.15.x versions are there. I had edited my post, but perhaps that was after your reply.
I’ll continue perhaps tomorrow or later in the week.
The patches found so far are all in
QTBUG-85279, Qt for macOS on Apple Silicon (arm64):
1. QtWebEngine patch for 5.15.3(+?):
https://bugreports.qt.io/browse/QTBU...comment-562355
2. Patches and process for Universal binaries on 5.15.2+; I’m not sure if it incorporates all the comments from that bug (and others?) as I haven’t tried yet but it seems complete:
https://github.com/crystalidea/macdeployqt-universal