v1.3 causes WSOD with "Call to undefined function _activityprofile_civix_civicrm_alterSettingsFolders()"

This is on D9 with Civi 5.49.1.

I haven't 100% caught up on the mixin business - but it seems like _activityprofile_civix_civicrm_alterSettingsFolders() and its friends (anything starting with _activityprofile_civix shouldn't be in activityprofile.php? Tim's blog post specifically mentions that activityprofile_civicrm_xmlMenu should be gone, which it isn't.