I could fix the issue by myself, getting some help from Copilot AI.
I wonder that you have no problem on your side because in the overrides:
html/com_content/article/default.php
html/layouts/joomla/content/post_formats/post_video.php
the code is not correct. At least for Joomla release 5.4.7
I guess it's the same issue for the other post_formats as in all files it use params instead of attribs.
Can you please explain why the blog options like post_format and parameters are now in attribs and how you will fix that issue in case of update of the template in the future?
Thanks!
In html/com_content/article/default.php
replaced
$post_format = $params->get('post_format', 'standard');
with
$attribs = json_decode($this->item->attribs);
$post_format = $attribs->post_format ?? 'standard';
in **html/layouts/joomla/content/post_formats/post_video.php**
replaced
$video_src = '';
if ($displayData['params']->get('video')) {
$video = parse_url($displayData['params']->get('video'));
with
$attribs = json_decode($displayData['item']->attribs);
$video_src = '';
if (!empty($attribs->video)) {
$video = parse_url($attribs->video);
...