Only the first level is shown in the menu

Dear AndKar, I am having the exact same issue, but I was wondering whether this is not something for the issue cue of the Menu Trail By Path Module. The issue here appears to be that the active-trail is no longer being set in the same way it used to be due to a change in Drupal Core. So maybe we should open this issue in the issue cue of the Menu Trail By Path Module...

Thanks for your answer. I think there is an issue created for this problem, see https://www.drupal.org/project/drupal/issues/3359511 🐛 [regression] missing menu active trail in Drupal 9.5.9 Needs work