i lost my patience and deleted/re-installed using device link.
ok, my account, code, friendslist and running games are back.
but all statistics are lost and the "restore" button doesn't function.
it hurts the more as i only just now noticed all the (new?) statistics screens for all actions, starting worlds, goals and 6-cost developments.
would have been very interesting to take a deep look into all of this
still no idea if it helped to bring back the notifications.
it was all in vain. notifications still down