@OP. The recordings you bought on SACD are bandwidth limited, so they are not going to benefit much from being transferred to SACD.
Esoteric's players decode DSD natively. However, for CDs the default Org non conversion setting, IMHO, does not sound as good as 2FS.
Unless you are using the K-03 as a USB DAC, the other upconversion settings are irrelevant.
I prefer the standard M1 filter setting but your mileage may vary - accessed under the PCMM heading in the menu.