They are indeed very rare in high sec. I found a few of them in 1.0 and 0.9 systems around Ryddinjorn. I don’t think they spawn in lower security high-sec.
The 1/10 is more common but doesn’t drop any deadspace loot ( Why do Minmatar DED 1/10 don't drop deadspace modules? )
Best way to find a 2/10 is in low-sec