Some of those issues might be caused by the underlying QtWebEngine. For others, qutebrowser might be responsible (I'm mainly thinking of https://github.com/qutebrowser/qutebrowser/issues/5376 which might be relevant).

In my day-to-day work, I only use Linux - so the Windows/macOS releases are pretty much "best effort" I'm afraid, until someone steps up to fix platform-specific issues there.