Re: I really like Linux except :]
Well, you can also use the text-based minimalistic installer and select which desktop you want (Caveat emptor - I think it doesn't do EFI boot):
http://archive.ubuntu.com/ubuntu/dists/disco/main/installer-amd64/current/images/netboot/mini.iso
You can also install several desktop environments simultaneously and change them from the login manager.
For a KVM virtual machine there's even a better way - dig down a little deeper in the directories:
http://archive.ubuntu.com/ubuntu/dists/disco/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64/
And download the kernel and initrd image of the installer. You can pass those to a KVM virtual machine to boot from.
I love the flexibility of this thing. I think that some time ago, if you started the installer kernel over a serial console it would even add the serial console option to the Grub defaults so you could access the virtual machine over serial console right after installation. This doesn't work with 18.04 so you better do this manually before rebooting the newly installed system. But I digress...