For the record, I've just realized that the system I reported it from was lacking bullseye-security updates, but I've checked it now on a fully up-to-date arm64 system with webkit2gtk 2.36.4-1~deb11u1 and it's still crashing in the same way.
- Bug#1016811: libwebkit2gtk-4.0-37: bullseye backpor... Sebastian Krzyszkowiak
- Bug#1016811: libwebkit2gtk-4.0-37: bullseye ba... Sebastian Krzyszkowiak
- Bug#1016811: libwebkit2gtk-4.0-37: bullseye ba... Alberto Garcia
- Bug#1016811: libwebkit2gtk-4.0-37: bullsey... Sebastian Krzyszkowiak
- Bug#1016811: libwebkit2gtk-4.0-37: bul... Alberto Garcia