Shireling
A Servant of King and Country
So let's use that scenario then. Suicide is a sin, no? So then God sinned themselves instead of just making everything perfect. Is that not proof of coming short of being omnipotent?
You're missing the point. The Death of Jesus wasn't a suicide, it was a sacrament. Jesus embodied the sacrificial lamb. In the Old Testament, Jews used to sacrifice their best lambs to atone their sins. They did this because lambs were innocent and pure. Jesus was the most innocent and pure person, thus his sacrifice is meant to parallel this process.
Its less of a suicide and more of a Jesus stepping in front of a firing squad and taking all the bullets for you if you want.