To understand why this issue occurs and the next plan of action.
When an AD User is trying to deploy a VM from the template, it gets stuck when trying to populate the "Select networks" screen until it times out. This is seen in SDDC versions 1.20v1 through 1.20v3 as well as 1.22v1 through 1.22v2.
This is caused by a known problem specific to 1.20v1 through 1.20v3 as well as 1.22v1 through 1.22v2.
This issue will be resolved in 1.20v4 & 1.22v3.
The viable workaround is to add the AD Users/Groups to the "cloudadmingroup" group following the process documented in KB5648.
https://kb.vmware.com/s/article/56489
AD users are not able to deploy a VM from a template. Cloudadmin will be able to deploy the VM.