The BaseParser::getRenderStrategy() does not get the parser's configured render strategy

Regarding

Another observation related to BaseParser::parse() method is that when using the fallback filter_output render strategy type, all markup is stripped, including markdown converted to HTML b/c this occurs after the conversion here within BaseParser::parse().

,

the order could be swapped to first filter out user provided HTML before converting markdown into HTML.

This could be a separate issue.

Ah, I think I figured out a work around.

Instead of invoking \Drupal::service('markdown')->parse(), which uses the default parser; l instantiated a parser by name with the parser's configuration. For example:

 drush php-eval "echo(\Drupal::service('markdown')->getParser('commonmark', Drupal::config('markdown.parser.commonmark')->getRawData())->parse('This is **BOLD**.'));"

This results in the expected output of
<p>This is <strong>BOLD</strong>.</p>

I have encountered the same issue and scenario as OP, after looking into this code. I've made change to assure the renderStrategy string may be fetched from the correct source, whether it's from the Plugin Configuration or the settings object.

Settings to needs review.

This should correct the behavior expected from the module's documentation → .