What you need to do is reregister the blog routes with the additional flag 'walled => false'.

This can be done in your elgg-plugin.php, copy the routes (exactly) from the blog plugins elgg-plugin.php and add them in the section 'routes' in your elgg-plugin.php.

You'll probably don't need all routes from the blog plugin, but most.

• collection:object:blog:owner
• collection:object:blog:friends
• view:object:blog
• collection:object:blog:group
• collection:object:blog:all
• default:object:blog

Make sure your plugin is below the Blog plugin in the plugin list.

Or you could register an event listener in a plugin bootstrap in the boot function for the event 'route:config', 'the list from above', then you can change the config for that route to add 'walled => false'.

Thank you for your respond.

So I must for example for the path

view:object:blog
add below code in elgg-plugin.php - or my understanding of this problem is horrible wrong?

elgg_register_route('view:object:blog', [
    'path' => '/blog/view/{guid}/{title?}',
    'resource' => 'blog/view',
    'walled' => false,
]);