Twenty Twenty-Four is exploring adding alternate template types for the home, index, single and page templates. While the effort in #51477 brings alternate template selection to pages, templates still do not have this capability.

There's currently not a method for someone to swap a template directly with another templateType.

Current

Template swapping in the site editor, for pages:

Proposed

If there are alternative templateTypes registered for a specific template, then surface the swapping functionality in the template inspector.

It could be in the verticalEllipsis menu (currently only there when customizations are present), or a button on the inspector, below the template's areas:

I lean towards the verticalEllipsis method, as it's more in line with what we have in pages, and doesn't make it too surfaced. Eventually it'd be nice to see previews of the templates in the sidebar, but for a quick addition something like this seems simple enough.