A template is a preconfigured virtual machine image that can be used to create new virtual machines quickly and easily. A template can include the operating system, applications, settings, and data that are required for a specific purpose or role. A type 1 hypervisor is a virtualization technology that runs directly on bare metal hardware, without requiring an underlying operating system. A type 1 hypervisor can provide better performance, security, and isolation for virtual machines than a type 2 hypervisor, which runs on top of an operating system. Verified Reference: [Template], [Type 1 hypervisor]

The first thing that the technician should do before installing a new server OS on legacy server hardware is to consult the HCL (Hardware Compatibility List) to ensure everything is supported. The HCL is a list of hardware devices and components that are tested and certified to work with a specific OS or software product. The HCL helps to avoid compatibility issues and performance problems that may arise from using unsupported or incompatible hardware. Migrating the physical server to a virtual server may be a good option to improve scalability and flexibility, but it requires additional hardware and software resources and may not be feasible for legacy server hardware. Low-level formatting the hard drives may be a good practice to erase any old data and prepare the drives for a new OS installation, but it does not guarantee that the hardware will work with the new OS. Making sure the case and the fans are free from dust may be a good practice to ensure proper cooling and prevent overheating, but it does not guarantee that the hardware will work with the new OS. Reference: https://www.howtogeek.com/190014/virtualization-basics-understanding-techniques-and-fundamentals/ https://www.howtogeek.com/173353/how-to-low-level-format-or-write-zeros-to-a-hard-drive/ https://www.howtogeek.com/303282/how-to-manage-your-pcs-fans-for-optimal-airflow-and-cooling/

Explanation
The first thing that the technician should do before installing a new server OS on legacy server hardware is to consult the HCL (Hardware Compatibility List) to ensure everything is supported. The HCL is a list of hardware devices and components that are tested and certified to work with a specific OS or software product.
The HCL helps to avoid compatibility issues and performance problems that may arise from using unsupported or incompatible hardware. Migrating the physical server to a virtual server may be a good option to improve scalability and flexibility, but it requires additional hardware and software resources and may not be feasible for legacy server hardware. Low-level formatting the hard drives may be a good practice to erase any old data and prepare the drives for a new OS installation, but it does not guarantee that the hardware will work with the new OS. Making sure the case and the fans are free from dust may be a good practice to ensure proper cooling and prevent overheating, but it does not guarantee that the hardware will work with the new OS. References:
https://www.howtogeek.com/190014/virtualization-basics-understanding-techniques-and-fundamentals/
https://www.howtogeek.com/173353/how-to-low-level-format-or-write-zeros-to-a-hard-drive/
https://www.howtogeek.com/303282/how-to-manage-your-pcs-fans-for-optimal-airflow-and-cooling/

Explanation
The most likely cause of this issue is that the UEFI boot was interrupted by a missing Linux boot file, such as grub.cfg or vmlinuz, which are essential for loading the Linux kernel and booting the system. The Es> prompt indicates that the system entered into UEFI Shell mode, which is a command-line interface for troubleshooting UEFI boot issues. The administrator can use UEFI Shell commands to locate and restore the missing boot file or change the boot order. Verified References: [UEFI Shell Guide]