You might be wrong on that Marvel. Shikigamis by themselves are already mathemathical geniuses who can find out formulas for immensely difficult problems. Calculating the Sanzu River which is said to be close to impossible is something Ran Yakumo did. By Gensokyo's terms and even to the outside world, they're super geniuses.
And somehow she cannot comprehend Yukari Yakumo's intelligence who can calculate 1000 variables in a second. It's like comparing a baby to an adult. Someone who's already known to be a supergenius is completely overshadowed by Yukari Yakumo, who is like Rick, lazy and never makes full use of their powers.
Oh Boundary Manipulation should be countered? Well the thing is... There are several WoG statements regarding the power of that.
Yukari's ability is the "manipulation of boundaries". It's a far-too-powerful ability that can, logically speaking, affect anything. Naturally, if she put this ability to its full use it wouldn't even be a game, so for the purposes of the narrative she fights within the spellcard rules.
https://en.touhouwiki.net/wiki/Strange_Creators_of_Outer_World/Who%27s_Who_of_Humans_%26_Youkai_in_Gensokyo/Yukari_Yakumo,_Ran_Yakumo,_and_Che
Yukari states in her own win quotes in Immaterial and Missing Power that she has no weaknesses, and even shooting, cutting, stabbing, hitting, or killing her is useless.
Her Imperishable Night profile also states that "she easily has enough power to annihilate all of Gensokyo if she so desires"[6], while the manual says that"the danger and power of her ability is beyond imagination".[7]
This is part of the world that can also make people cease to exist by erasing past, present and future, manipulating fate, manipulating life and death, unleash nukes, make parallel worlds (Toyosatomimi) that have the moon and a planet nearby.
One correction though. Fart, the cloud that you were talking about being a higher dimension, is from another dimension. However it's the same issue as comparing science and magic. He needed anti-matter to kill the gaseous being sure, but Yukari has access to that too. With ease.
I'm not trying to say Yukari wins tbh, although I do side with her. Naturally Touhou is vague and frankly I agree with you on prep time debates. However it still doesn't hold the fact that Rick is prone to mistakes too. How does one exactly counter bounder manipulation? And what if Yukari pulls out another trick that counters what counters the bounder manipulation. Which in turn reveals Rick has a trump card for and Yukari has a trump card for again and then again- it's literally the battle of ass pull trump cards. Sides, Yukari still has the 2-D based ability and the capability to escape with the range of her gaps.
But I'm saying that WoG statements in Touhou exists too.
Oh and still believing it's a tie, slightly leaning on Yukari.