During this process.
As stated before, the only thing they truly needed to guard against was Konohagakure's response. As for Akatsuki, there was only a certain possibility of involvement.
After all, based on the plot of the Original Work and the intelligence received in this life, Shōji personally believed that Obito was unlikely to let Akatsuki—or even himself—step in to support the Three Great Shinobi Villages. At most, he would provide a certain degree of assistance in intelligence or other areas. Obito most likely wanted to see these shinobi villages clash with and weaken one another.
Who won and who lost—did that really matter?
Not at all!
As long as they bought enough time and weakened all Four Great Shinobi Villages, creating better conditions for the Tailed Beast Capture Plan, that would be enough!
Obito generally would not care about anything beyond that.
Therefore, Shōji's precautions against Akatsuki supporting the Three Great Shinobi Villages were merely born of caution.
To be honest, Shōji truly did not think Obito would intervene. The only one that would genuinely send aid to rescue Sunagakure was Konohagakure!
Kirigakure was too far away and simply could not make it in time. Kumogakure had Fourth Raikage A, their greatest spy, delaying them. No matter what happened, they could perfectly stall things until Sunagakure was destroyed!
While remaining in the village and waiting, Shōji kept his attention fixed on Konohagakure. The moment he received word that Konoha's army had mobilized—
Shōji decided to act!
Konoha's army could not be allowed to interfere with Kitsuchi's main force!
Holding back Konoha's army—
And perhaps using this opportunity to inflict serious damage on Konohagakure—was one of Shōji's objectives!
And before setting out—
There was one small promise Shōji needed to fulfill: removing the restrictions of Neji Hyuga's Caged Bird Seal!