Yes Ubuntu Server would be the thing to try. Apart from time, it will cost $0 to try.
It can run DSD256 but the question is can it run EC modulators like you are used to. Probably not but you could try to find out. ASDM5 and ASDM7 (non EC) are still high quality modulators.
After you install Ubuntu it’s something like the below to get HQPlayer Embedded (different license to your Desktop license) and Roon Server. You could try Ubuntu Desktop and your existing HQP Desktop license on there maybe.
HQP Embedded on Ubuntu Focal:
sudo apt-get -y update
sudo apt-get -y dist-upgrade
sudo apt-get install alsa-utils
wget https://www.sonarnerd.net/src/focal/libgmpris_2.2.1-8_amd64.deb
sudo dpkg -i libgmpris_2.2.1-8_amd64.deb
Add following steps prior to installing hqplayerd package:
wget -q -O - https://repo.radeon.com/rocm/rocm.gpg.key | sudo apt-key add -
echo ‘deb [arch=amd64] Index of /rocm/apt/debian/ xenial main’ | sudo tee /etc/apt/sources.list.d/rocm.list
sudo apt update
sudo apt-get -y update
sudo apt-get -y dist-upgrade
sudo wget https://www.signalyst.eu/bins/hqplayerd/focal/hqplayerd_4.25.2-85_amd64.deb
sudo dpkg -i hqplayerd_4.25.2-85_amd64.deb
sudo apt install -f ; sudo apt autoremove --purge ; sudo apt clean
systemctl enable hqplayerd;systemctl restart hqplayerd
sudo apt install -f (installs dependancies)
sudo reboot
Roon Server:
sudo apt install curl
sudo apt install -y cifs-utils
sudo apt-get install ffmpeg
curl -O http://download.roonlabs.com/builds/roonserver-installer-linuxx64.sh
chmod +x roonserver-installer-linuxx64.sh
sudo ./roonserver-installer-linuxx64.sh
sudo apt install -f (installs dependancies)
sudo reboot