Just want to confirm with you DL experts here:Should I credit this KE operated flight (DL marketed) to DL or VS?

I got the trial instant Silver mainly to see if it would increase my MUA upgrade chance, but later found out that it's a no-go for KE operated flights at all, so it seems the Silver only gives a priority boarding nothing else. I don't think I would be able to either accomplish the challenge and keep the DL silver by this round trip alone. Also so far really seeing my DL activity increase significantly due to the fact that I'm in IAD/DCA. I do understand that DL miles do not expire, which is the exact reason I still have the 89k miles from years go (a credit card and some flight activities)

Y fare on DL marketed and KE operated long haul, around 14000 miles RT. It seems that I get about the same 195% from DL Silver when crediting to DL, 150% to VS as a regular VS member.

I haven't really found or fully understood the sweetspots of DL redemption, but I do see use cases for VS redemption (east coast to Europe, and even to Asia). Even for DL redemption, it a lot of times requires much less FB points or VS points compared to using SkyMiles.

I just online checked in for tomorrow's flight, do I still have time to change it say via chat? Should've confirmed this with DL experts here earlier. Thanks a lot.