You can use qemu utilities to convert your Linux disk image to VDI which you can then import into VM Workstation or Virtualbox:
qemu-img convert -f qcow2 -O vdi your-image.qcow2 your-image.vdi
One thing you might run into is that Ubuntu server images often use VirtIO drivers, So you may have to make adjustments for that. Or you may run into the need for other drivers that VM Workstation or VirtualBox don't provide.
https://documentation.ubuntu.com/server/how-to/virtualisation/qemu/#qemu
https://systemadministration.net/converting-virtual-disk-images-qemu-img/
ETA: There is also StarWind V2V Converter