I am happy to say I got this Crypt to bloom. I would say It was quite easy, just beech tree litter (mixed with some Seramis = clay based substrate), pH round 4,5 (EC approx. 250-350 uS/cm) and after 8 months I got this pretty spathe.
(Note. I took these photos at night. I rather add more, because the quality can vary).
The pretty leaf pattern this Crypt has can be found here: C. auriculata ‘Tiger stripes’ ‘Julau’ – leaves