I was encouraged [1] to use the storage encryption mechanism of libvirt [2]. However, it is not clear to me how to generate a corresponding encrypted volume. Preferably, I would like to use virt-install to arrive at such an encrypted volume, similar to e.g.

virt-install --connect qemu:///system -n testImage  -r 2048 --os-type=linux --disk testImage.img,device=disk,bus=virtio,size=8,sparse=true,format=raw --os-variant debian10 --vnc  --location  ftp://ftp2.de.debian.org/debian/dists/buster/main/installer-amd64/

I already asked a related question on server fault [3], but this is a better targeted audience. Sorry for double-posting.

[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=933385

[2] https://libvirt.org/formatstorageencryption.html#StorageEncryption

[3] https://serverfault.com/questions/986488/how-to-enable-volumeencryption-during-virt-install