When the Anapanasati Sutta refers to seeing Dhamma (steps 13 to 16), it refers to:
13. Impermanence (unsatisfactoriness & not-self)
14. Viraga (dispassion)
15. Nirodha (extinguishment of defilements - Nibbana)
16. Relinquishing (all selfing)
These are not mere "things". These are Higher Truth.
The above does not appear to be the meaning of "ritta" and "rittaka". The idea of "reality" appears too vague above. "Ritta" generically means "devoid", such as in:
In the Phena Sutta, "ritta" is used to describe how the five aggregates are devoid of any substance, meaning & intrinsic worth. That the five aggregates are devoid of substance is their "reality" therefore I think using the term "without reality" is too vague and confusing.Rid of sensual pleasures, expecting nothing,
Kāmehi ritto apurakkharāno,
The above, which sounds like "sunnata", appears to be another generalisation. I would suggest to try to be more accurate or specific with these Pali terms. I doubt "rittaka" is the exactly the same as "sunnata".