TYPO3 custom content element template is not being rendered

I'm trying to create my own content element in TYPO3 v12, but the template of it is not being rendered. Based on the template code, the HTML code that should be displayed would look like this:

<header class="header">     
    <div class="af6bus__banner">Test</div>
</header>

However, what I'm getting is:

<header class="header"></header>

I've checked if the typoscript is included in the root page, which was the case. I've also tried removing the rendering registration which resultet, as expected, in the error "content element has no rendering definition".

Here is my current code:

af6bus/Resources/Private/Layouts/Default.html

<html xmlns:f="http://typo3.org/ns/TYPO3/CMS/Fluid/ViewHelpers"
      data-namespace-typo3-fluid="true">
    <span class="anchor" id="top"></span>
    <f:render section="content" />
</html>

af6bus/Resources/Private/Templates/Default.html

<html xmlns:f="http://typo3.org/ns/TYPO3/CMS/Fluid/ViewHelpers"
      data-namespace-typo3-fluid="true">

<f:layout name="Default" />

<f:section name="content">
    <header class="header">
        <f:cObject typoscriptObjectPath="lib.dynamicContent" data="{colPos: '100'}" />
    </header>

    <main class="main">
        <f:cObject typoscriptObjectPath="lib.dynamicContent" data="{colPos: '0'}" />
    </main>

    <a href="#top" class="scroll--top"></span></a>

    <footer class="footer">

    </footer>

</f:section>
</html>

af6bus/Resources/Private/Templates/Banner.html

<html xmlns:f="http://typo3.org/ns/TYPO3/CMS/Fluid/ViewHelpers"
      data-namespace-typo3-fluid="true">

<f:layout name="Default" />

<f:section name="content">

    <div class="af6bus__banner">Text</div>

</f:section>

</html>

af6bus/Configuration/TypoScript/Setup/template.typoscript

page = PAGE
page {
  10 = FLUIDTEMPLATE
  10 {
    templateName = TEXT
    templateName.stdWrap {
      cObject = CASE
      cObject {

        key.data = pagelayout

        default = TEXT
        default.value = Default

        pagets__default = TEXT
        pagets__default.value = Default

        pagets__nobanner = TEXT
        pagets__nobanner.value = NoBanner
      }
    }

    layoutRootPaths {
      10 = EXT:af6bus/Resources/Private/Layouts/
    }
    templateRootPaths {
      10 = EXT:af6bus/Resources/Private/Templates/
    }
    partialRootPaths {
      10 = EXT:af6bus/Resources/Private/Partials/
    }

    variables {
      siteName = TEXT
      siteName.value = {siteLanguage:websiteTitle}
      siteName.insertData = 1
      homePid = TEXT
      homePid.value = {$homePid}
      footerPid = TEXT
      footerPid.value = {$footerPid}
    }
  }
}

lib.dynamicContent = COA
lib.dynamicContent {
  10 = LOAD_REGISTER
  10.colPos.cObject = TEXT
  10.colPos.cObject {
    field = colPos
    ifEmpty.cObject = TEXT
    ifEmpty.cObject {
      value.current = 1
      ifEmpty = 0
    }
  }
  20 = CONTENT
  20 {
    table = tt_content
    select {
      orderBy = sorting
      where = {#colPos}={register:colPos}
      where.insertData = 1
    }
  }
  90 = RESTORE_REGISTER
}

## Banner-Template
tt_content {
  af6bus_banner =< lib.dynamicContent
  af6bus_banner {
    templateName = Banner.html
    dataProcessing {
      10 = TYPO3\CMS\Frontend\DataProcessing\FilesProcessor
      10 {
        references.fieldName = assets
      }
    }
  }
}

Solution

So after some trial and error I have finally made it work. Now I'm not sure wether or not this is the ideal solution, but it works.

In my TypoScript file af6bus/Configuration/TypoScript/Setup/template.typoscript I adjusted the rendering and replaced lib.dynamicContent with lib.contentElement. I also removed the .html from the template name. This is how the code looks now.

tt_content {
    af6bus_banner =< lib.contentElement
    af6bus_banner {
        templateName = Banner

        templateRootPaths.100 = EXT:af6bus/Resources/Private/Templates/

        dataProcessing {
            10 = TYPO3\CMS\Frontend\DataProcessing\FilesProcessor
            10 {
                references.fieldName = assets
            }
        }
    }
}

As for the template, I simply changed the section name from content to Main.