UPDATE!: Credit where credit is due!!! Excellent and diligent work, all. With the release of Preview 2, seeing MASSIVELY improved stability with Direct X 12 and even Path Tracing with fairly gratuitous settings. Can report on Windows 11, reasonably high spec system, Metahumans has been restored to full functionality and seems vastly more stable.
Sill waiting for the other shoe of course, but persistent crash issues seem to have been substantially rectified for previously experimental features.
A testament to responsive community-driven development. Excited to experiment with all the new features. Our thanks to the team. Respect.