This is correct - all TERRA STABLES are depegged.
I have not followed the discussion, but did see this part about the KRW valuation (and whether it is depegged or not). I had the pleasure of working with @johny (Faffy) (who did quite extensive research) in looking deeper into the Market module and how the system values LUNA v1 vs. the TERRA STABLES (in research)(see research at the bottom - links).
The oracle pricing for stables are derived from their real world fiat values (and based in the replenish pool side for the TERRA pool [as opposed to the LUNA v1 pool]). That means the system sees all the stables at their real world prices. The oracle for LUNA v1 comes from central exchange pricing.
SDR (actually usdr - micro SDR) is the price stability between the two pools.
The link @godoal mentioned return back how many of the Stable Denomination that 1 LUNA v1 would purchase:
So, on a market swap since 1 LUNA v1 = 0.000157 USD (since the system takes UST as USD at $1), and 1 LUNA v1 = 0.20027 KRW (since the system takes KRT as KRW at 1KRW [or $0.00079 USD currently]).
However, since 1 UST (128.87 LUNA v1 or $0.02048) does not equal 1 USD (6,369 LUNA v1 [1 / 0.000157] or $1), then 1 KRT (0.09482 LUNA v1 or $0.0000149) does not equal 1 KRW (4.99991 LUNA v1 [1 / 0.20027] or $0.00079)
So, in other words since all the stables are from the same side of the replenish pool, and the system values them on their real world values, the swaps between them will be equivalent to their real world exchange rates in terms of percentages (they would exchange with each other value wise - ie. they are each the same percentage wise devalued). But, if you turned on the swap for LUNA <> TERRA STABLES, it would see each of the stables at the same price as their real world fiat values (rather than what UST is exchanging for on central exchanges, or the other stables are exchanging for between LUNA <> TERRA STABLES on other DEX’s based on their actual traded values).
So, yes, all the stables are depegged.
I hope that helps a little bit.