i think they tried to say that the prince and the marques were opposed to stop the smuggling (judging from their reactions). tho i dont think it was just them but prolly the 2 were the ones who were explicitly against it.
but I agree. the problem wrapped itself up too soon without even any background as to why the 2 were even so opposed to it. did the marquis have a drug selling business? was the prince an opium user? i dont get it. and then there's the excessive payoff. haha i feel like the author just needed a reason to lower the tea price to make it more accessible. but yea i still love this manga
she does play a part at times but it just feels a little forced with this one. but i mean, come on, the deciding factor to the delegates' cooperation.. was coz they were served good tea and meals?
with the opium thing it just felt like she meddled with something that'll get resolved on its own at some point. her involvement just seemed to hasten things up.

Honestly, in the previous chapter, I thought the prince opposed smuggling so that means he wants it to stop right? But turns out, he supports it... I might have a weak reading comprehension, maybe I misunderstood that? Antway, the topic was brushed off almost immediately anyway, so I guess that's that. Tbh, the story's too fast paced, the problems comes and goes in a span of 2 chapters so I guess I shouldn't think too much of the problems they present from now on, lol. I still like the story ofc.