Between my native tongue of Finnish and then English, for example, in English people often say "fourteen hundred", meaning 1,400, but in Finnish pretty much nobody ever says that, it's always "a thousand four hundred" (translated literally).
Being able to feed millions of soldiers at any given time in a pre-industrial society is impossible if you think about the whole logistics every day this armies consume millions of tons of grains this kind of feat is still incredibly hard now a days now imagine this world without fertilizers and mechanized farming then the only option of this happening would be they still have millions of boys ready to the meat grinder but they cant be sent because they are farming or they really have lost most of the population minus the small portion without classes and the children so with some kind of super magic way all of this grain amd varyous suplies are harvested and made. this is a absolute logistical achievement with pre-industrial transports aka donkeys, horses, and maybe the various other magic beasts that are tamed.
I think on the contrary, in times of crisis like this it would be absolutely foolish to sabotage himself over some petty reason. He's sending them over because he knew they're the most capable and competent group available to take the task. Just my 2-cents.
Nah, he just wants them as far from him as possible on a suicide mission. It sinks in more in the LN that Allen is perceived as a huge threat not only because of his power, but also because he has thwarted the schemes of the Crown Prince's faction on multiple occasions.