@glomoro
Everything you said would indeed be plausible. However, TUTU is a master of illusion, of symbolism and of mind games. As much as there is to support your claims, there is just as much to support those that Saya has been under tremendous stress because of the escalating situation in Mirage and of the happenings at court.
We must not forget that in Chapter 7, Consort Huan has received direct orders from Mirage to dispose of Ling Zhi. In Chapter 11, she offers Ling Zhi the possibility to bow out once. Ling Zhi refuses. She employs a first manner to get rid of Ling Zhi. However, no one asks why Consort Huan would need to get rid of Ling Zhi to begin with. The Emperor is a man who has been chased out of the palace by the Empress Dowager, he has been stripped of administrative, legislative, executive power and has taken refuge in the harem.
To foster an alliance, Consort Huan must make the harem unlivable for him and force him to choose one side. Either the Empress Dowager, who so to say, only needs him to maintain the Pact of Non-Aggression between Mirage and the Human Empire until she can with confidence attack the greatest army among the foreign peoples (it would be interesting to ask, why this greatest of armies has not taken part in the Great War of Conquests, something the Fire People hold against them and how aristocrats can send a Supreme Commander to exile when he could have started a military putsch any time). On the other side, there is the Mirage State. Now, if the Emperor allied with the Mirage State, he would be forced to express himself against the war. This could undermine the Empress Dowager's military influence by causing civil unrest. If we remember well in Chapter 18, it is known that the Empress Dowager coerces civilians into the army (we can see the villagers from Qingyan's hamlet walking away enchained). If the Emperor were to voice his support against the war, it would give those people reason to rebel, create instability that the Mirage State could exploit to attack and crush the Human Army.
However, the Emperor being the Emperor, he has taken Saya's measure as soon as she has stepped foot into the harem and has started throwing concubines at her to make her believe he was comfortable enough in the situation he found himself in and would in no way seek to anger the Empress Dowager. This way, he kept Saya occupied and nervous.
Then we have Chapter 23 that increases Saya's fear by a notch. She sees what happened to the Snow People who were obliterated, she sees what happened to Bingjian (Snow King) and she explicitly tells herself that this could happen to the Mirage People. And that she needs to force the Emperor into an alliance. As well, whenever she thinks of Ling Zhi, she puts her in relation with the Emperor. The Emperor has taught her to evade Consort Huan. The Emperor has given her the rank of Consort to act as a buffer against Consort Huan. The Emperor needs to be forced into an alliance. Rather than Ling Zhi, Consort Huan is obsessed with the Emperor.
In Chapters 31 and 32, she is seen staring at the Mirage Golden Sun for what seem to be ongoing moments. She is indeed obsessed and neurotic, but Ling Zhi is only a symbol for her, not a true person. It is an obstacle that needs to be removed for Mirage. Consort Huan is also uninterested in the administrative powers that she held as main consort, she voices her contempt of them in Chapter 32. Hence, it is difficult to say whether she ever desired power for the pleasure of having power or whether it was a means to make the Emperor's life as miserable as possible.
Now about Shana and the other Mirage women, they were not in the same position as Consort Huan. In fact, seeing how Shana was the main instigator of unrest in both Chapters 6 and 10 makes one wonder whether she is not the one enjoying the power the Mirage women hold in the harem, power they get mainly through Consort Huan. Consort Huan on the contrary, in both Chapters 10 and 26, shows guilt towards other foreign peoples since Mirage did not fight alongside them during the Great War of Conquests. Shana desires to preserve her life (and who wouldn't). She reminds Consort Huan that they are nothing but a tool given in mariage in Chapter 26 and that there should stop their allegiance to Mirage. Shana is a woman scared for her life and that of her family (which is normal). But she is not (as she, herself admits later on), in the same position as Consort Huan who has other pressures forcing her to act. She does not question so much Consort Huan's desire to destroy Ling Zhi as she questions the consequences failure would have on their lives. But Consort Huan's life might be considered as the possession of Mirage, not her own.
If Ling Zhi, the Emperor's favorite had appeared with the Golden Sun on her dress in this chapter, this would have created an immediate cleave between the Empress Dowager, who tolerates the Emperor for political reasons, and the Emperor and would have forced him to look for shelter elsewhere. Finally. But the Emperor is the Emperor. He manipulates the Empress Dowager, let alone a simple, rash and narrow-sighted spirit as Consort Huan.
What is amazing with TUTU is the fact that she never tells you what you are supposed to think but lets you draw your own conclusions. This is the position I have chosen to defend. But truth being said, your position is just as plausible. I mean, we spend hours on the Discord trying to make sense of what TUTU is trying to tell us. It is all very exciting. Where I am concerned, Chapters 37 and 38 sell the deal where Consort Huan, or rather at that point, Saya's motivations are concerned. And especially the end of 38. But as said, choose a side, stick to it, you will find enough arguments to defend it either way. It's TUTU, she never gives you anything on a silver platter.