Having the same problem since march : W11 virtual machine randomly shutting down (while using Lego Digital Designer, a 3D CAD software, not XL). The delay before quitting is variable. From 15 min to 1 or 2 hours (?) maybe depending on the activity (problem of memory leak or progressive saturation of a resource ?) Recent upgrades of Parallels Desktop don't solve the problem. Going back to Parallels Desktop 26 2.1 (pre-march version) resolves the issue, even with the most recent Windows upgrades It seems that something wrong was introduced in 26 2.2, not resolved since :-(
More discussion happening here: https://forum.parallels.com/threads/win-11-crashing-probably-excel-related.370012/