The docs have a section for this symptom, Windows Server 2025 hanging at 0% CPU: https://docs.xcp-ng.org/troubleshooting/windows-pv-tools#windows-server-2025-hangs-randomly-with-0-cpu .
Besides the Viridian flags you've already set, it says to revert useplatformclock and useplatformtick with bcdedit if they were ever set in the guest.
Your earlier thread showed a VM created from the "Other install media" template, so it's worth checking which template this one came from, since the Windows templates bring their own Viridian settings.
I don't think the QEMU SIGTERM is the cause, though: when I force-shut down a VM on a lab host, qemu-dm logged that exact terminating on signal 15 line, sent by xenopsd-xc (ps -o comm -p 1526469 will tell you on yours), so yours most likely just matches your forced shutdown around 10:20 on 5 Oct.
If it freezes again after that, the memory dump procedure further down the same page (https://docs.xcp-ng.org/troubleshooting/windows-pv-tools#how-to-gather-kernel-memory-dumps-for-in-depth-troubleshooting) is likely what people who know Windows guests better than me would want to see.