Installed a copy of PureOS 11 Crimson into a Gnome Boxes VM. Was having this maddening problem where the entire VM would freeze for 10-15 seconds, then unfreeze for a few seconds, then freeze again. Didn’t matter if you were actively typing or moving the mouse, or just letting it run an operation.
Checked Gnome system monitor to make sure the host system wasn’t resource constrained. My first suspicion is that it was a disk I/O issue.
Then ran sudo apt update; sudo apt upgrade -y; sudo apt autoremove -y. It took it a while to get through all the updates. Rebooted the VM and the freezing issues appears to have been eliminated so far.