>sitting Queen to come kowtow to their Emperor in person

I’m gonna need a source for that b/c that’s not how the tributary system in China worked. Never did the kings of Dai Nam (Vietnam), Joseon (Korea), or other tributary states personally come to Beijing nor were they required to. Instead, the diplomatic convoy made the token recognition and brought gifts, then they received gifts from the Chinese emperor in return, usually of much higher value. It was such a profitable exercise that some tributary states would send convoys multiple times a year until the emperor had to limit their visits. So unless there’s something special about the queen of England to warrant special treatment I can’t see how a personal visit was demanded