It is my understanding that QWebEngineView is available in both PySide6 and PyQt5 via the QtWebEngineWidgets class:
Code:
from from PyQt5.QtWebEngineWidgets import QWebEngineView
from from PySide6.QtWebEngineWidgets import QWebEngineView
Using my helper module (plugin_utils.py), you should be able to unify that with:
include plugin_utils
from plugin_utils import QtWebEngineWidgets
weview = QtWebEngineWidget.QWebEngineView()
As for the "Error Parsing Result XML" ... that is a plugin launcher/wrapper error that typically occurs when there's an issue with the data being returned from the Python plugin process to Sigil's C++ routines.
See any of the three Sigil ePub3 reader plugins (EpubJSReader, BibiReader, ReadiumReader) for examples of QWebEngineView being used in a plugin that supports both Qt5/PyQt5 and Qt6/PySide6 versions of Sigil.