According to Nutanix Support & Insights3, you need to install the Nutanix AHV plugin for Citrix Virtual Apps and Desktops on Delivery Controllers (also called the MCS plugin SDK) to create and manage Citrix-provisioned VMs in a Nutanix AHV infrastructure environment. 

an action that the administrator should take to identify the virtual desktops in the environment that are using the most resources and causing resource contention is Filter the virtual desktops by Constrained: High. Constrained is a metric that indicates how often a virtual machine is unable to get its requested CPU resources. A high value means that the virtual machine is frequently starved for CPU and may experience performance degradation. By filtering the virtual desktops by Constrained: High, the administrator can see which ones are suffering from resource contention and take appropriate actions such as migrating them to less loaded hosts or increasing their CPU allocation.

https://portal.nutanix.com/page/documents/details?targetId=Prism-Central-Guide-Prism-v6_0:mul-tasks-view-page-pc-r.html

A high CPU Ready time means that the vCPU is waiting too long for the pCPU, which can result in poor performance and slow responsiveness of the virtual machine (VM).

According to Nutanix best practices2, one of the factors that can affect CPU Ready time is the host power policy. The host power policy determines how aggressively the host will try to save power by reducing the frequency or voltage of the pCPUs.

The recommended host power policy for Nutanix clusters is High Performance, which disables any power saving features and ensures that the pCPUs run at their maximum frequency and voltage.

This answer seems to explain why desktops on one host are running slower and have higher CPU Ready times than on other hosts, as they may be suffering from reduced pCPU performance due to a lower host power policy.

Citrix NetScaler VPX is a virtual appliance that provides web and application load balancing, secure and remote access, acceleration, security and offload features1. To set up and configure a Citrix NetScaler VPX appliance, you need to download it from the Citrix website, install it on a hypervisor such as Citrix XenServer or Microsoft Azure23, and log on to the console using the nsroot credentials2.

To expose the Citrix NetScaler VPX private VIP to the internet in order for users to be able to access the Citrix VDI desktops upon a DR failover, one possible solution is to use a floating IP address. A floating IP address is an IP address that can be dynamically assigned to an instance by using API calls. It allows you to redirect network traffic from one instance to another without changing any DNS settings or client configuration.

The Citrix Optimizer tool is used to prepare Windows operating system images for use in a virtual desktop environment. Some of the actions that it takes to improve the gold image creation process include:

• Optimizes user environments for better performance: The tool removes unnecessary or redundant services, features, and applications from the image, which can improve performance and reduce resource usage.
• Uses built-in templates to perform optimizations: The tool comes with pre-configured templates that are optimized for specific environments, such as virtualdesktops or server workloads. These templates can be customized based on the specific needs of the organization.

https://support.citrix.com/article/CTX224676/citrix-optimizer-tool

https://docs.citrix.com/en-us/workspace-environment-management/service/using-environment-management/system-optimization/citrix-optimizer.html

One of them is Nutanix Frame, which is a cloud-based service that delivers virtual apps and desktops from any cloud provider or on-premises datacenter.

Nutanix Frame simplifies VDI deployment by providing automated cloud resource orchestration, user session brokering, and environment administration.

Another solution is Nutanix Citrix Cloud, which is a hybrid cloud solution that integrates Nutanix HCI with Citrix Virtual Apps and Desktops service.

Nutanix Citrix Cloud enables VDI deployment by providing centralized management and delivery of virtual apps and desktops through Citrix Cloud Services.

According to Nutanix best practices2, one of the steps needed for deploying VDI with Nutanix Citrix Cloud is to configure the PE Citrix Connection.

This step involves creating a connection between the Nutanix Prism Element (PE) cluster and the Citrix Cloud account, which allows Nutanix to register as a resource location for Citrix Cloud Services.

This connection also enables Nutanix to provide performance metrics, alerts, and actions for the virtual apps and desktops running on Nutanix HCI.