While KTo has great equity, raising a wet flop against a range advantage is overplaying our hand; calling allows us to realize equity more safely.
Raising here is a significant mistake; we should call to realize our equity. Our open-ended straight draw is strong, but the SB has a massive range advantage on this texture.
Note: Raising with an OESD on this board is too aggressive; calling is much higher EV as it keeps SB's bluffs in and avoids getting blown off our equity by a 3-bet.
Once the flush completes and SB leads into us, our hand's value plummets. We must fold as we no longer have the required equity to continue against a range that now includes many flushes.
Note: Calling the turn lead is a mistake; the 3s is a terrible card for our range and we are drawing nearly dead against SB's value range.
Folding is the only option here. The board has four spades and we have nothing but King-high; we lose to every pair, every flush, and even most of SB's missed straight draws.