the last episode was good it had some funny moments like Soifon asking who Gonryōmaru belongs to the Hōzukimaru & Ikkaku was good
the Zanpakutō Unknown Tales arc should at least last 25 more episodes meaning 38 episodes (41 if you include the 3 filler episodes before it )in total. i could see them making 11 more episodes of filler after that that aren't related to the arc making 52 episodes so the 52 isn't that far fetch