Building on my tags from this post for the custody battle au, I truly think the one way SJ!SQQ would try to work together with Yue Qingyuan versus against him in regards to poaching SY is when they realize that Luo Binghe is trying to court him lmao
SQQ was already aware of this possibility back before the Abyss with how LBH followed after SY on Qing Jing like a little duckling. However, back then he was able to keep a better eye on it (Plus was totally using SY's doting on LBH to get him to stay on Qing Jing more and spite YQY) Now knowing LBH's demonic nature and casting him into the Abyss, SQQ is taking the matter of keeping LBH from courting SY Way more seriously.
Especially since LBH knows that SY doesn't frown upon him for his demon heritage (and actually finds it cool). So he did not wait to try his courting attempts immediately after leaving the Abyss. SQQ and YQY are naturally quite protective over their pseudo-son and Know it would just take one look at LBH to get SY to cave to his courting (even if SY is too oblivious to realize "Come to the demon realm with me" is Not just a fun buddy trip and more "Be my empress <3")
Now it's become an the enemy of my enemy is my friend for SQQ, in which he and YQY are pulling all the stops to make sure that SY and LBH are not together. They've fought over custody for too long for this demon to come and bride nap him okay. SY just thinks they hate him because he's a demon/heavenly demon and is trying so hard to convince them to raise the ban of him from Cang Qiong by arguing for his upbringing and human half (#1 binghe defender fr). Little did he know that isn't even the biggest reason the ban is in place 😭
Ironically the ban from Cang Qiong isn't even stopping LBH from visiting SY. Sure, he can't use Xin Mo without setting off alarm talismans, but that doesn't stop his dream powers! So this whole time SQQ and YQY are thinking they're doing a great job of ensuring the two of them aren't alone together. Meanwhile, LBH is taking him on dream dates this whole time.
YQY playing the ever diplomatic sect leader has created various difficult and near impossible courting requirements (all of which have been run by SQQ) for him to even consider letting LBH court his head disciple/son. Telling him to find this or that dangerous creature/flower in hopes that he just gives up. But LBH ain't a quitter (and he knows how much SY loves this kind of shit and was already planning to get some of this stuff anyways lol).
