A newer way to expand/insert all items in an object is using the ${{ insert }} key:

parameters:
- name: Location
  type: string
  default: 'westus'

extends:
  template: Template.yml
  parameters:
    ${{ insert }}: ${{ parameters }}

Docs: https://learn.microsoft.com/en-us/azure/devops/pipelines/process/template-expressions?view=azure-devops#insertion