Not even "pretend to be the Messiah" ...
... for Bibi, things are a lot more trivial than that: given his current situation, he must either remain PM (and, ideally: achieve some kind of a "so heroic that basically unassaible" status, or - failing that - at least remain at war and credible in terms of "horse, mid-race, ... you get the drift"), or he has the other option of, well ... dealing with his multiple indictments and most certainly not being helped if his newly acquired image is "the man responsible for this entire debacle".
His coalition partners (if one can call racial supremacist ultra-far-rightwingers that) meanwhile have some ideological goals to meet - and the opportunity looks too good to miss to them!
Technically, there are arguably myriad "better for Israel, from a strategic and geopolitical perspective" ways this could be going right now. But they are not "better for Netanyahu and his racial supremacist cronies"!