Block id is removed in the block component

The above example is almost right but there's a typo. It should be:
plugin_id ? 'block--' ~ plugin_id|replace({"_": "-", ":": "--"})|clean_class,
This should really be fixed in the main theme since all the layout builder blocks do not print any class.

Update with drupal 10.2 and Radix 5.0.11

This code will ad all classes in a second class tag.

{% if html_tag %}
  <{{ html_tag }}{{ attributes|without('id').addClass(classes)}}{{ attributes.setAttribute('id', clean_id) }}>
{% endif %}

Correct code:

{% if html_tag %}
  <{{ html_tag }} {{ attributes|without('id').addClass(classes).setAttribute('id', clean_id) }}>
{% endif %}

No longer supported/outdated, closing - feel free to open MR.