Probably The Great Ruler, as the other two feel a lot more... Young? Juvenile?
Idk, it might just be the fact that I read them years ago, but the MCs felt less mature.
I might go for a re-read in the next future however.
I am liking, a lot more than I expected, Dragon Prince Yuan, so that is good.
Let's see how it continues.
P.S.
You could simply go in order with BTTH, WDQK and then TGR.
The references are not big, but it feels nice to say "Ah, I recognize that name".