@encryptblockr
Yes, and I documented the process I used a while back here: https://xcp-ng.org/forum/topic/6821/cloud-init-success
I just use the stock cloud image .ova file as my base image. for Ubuntu templates. I use the noble (24.04) image in quite a few instances from my template with success.
Your post mentions cloud-init is not working - some tips to try troubleshooting, when the new VM is provisioned, (assuming you are able to login) I usually run "cloud-init status --wait" and when that completes I run "cloud-init status --long" for a summary of the state. Then you can grep for WARNING in /var/log/cloud-init.log for clues.
If you weren't able to login to the VM - make sure your cloud-init config has the userid's, passwords and SSH keys you will need for login. See the example I posted here, since those are what I use in my lab or some variation.
Feel free to share any troubleshooting steps you have taken, and I will help any way I can. I have setup hundreds of VM's from templates using cloud-init so I have seen many of the challenges it brings.