Inserting the dynamic meta title and meta description fails

For the title you don’t use content=""
I think you shold get familiar with how the meta tags are used before trying to add dynamic values to them.

So title is used like:

<title>{{dyniac_data}}</title>

description meta tag:

<meta name="description" dmx-bind:content="dynamic_data">

Also as explained in the same topic you posted a while ago, you need to set the app root option to page, not to body: