Christ cannot be there to change the bread and wine into his Body and Blood as he did at the Last Supper. In his place (alter Christus) is the priest, empowered through his ordination to celebrate the Eucharist in this very special way.
Jesus does that every time when partaking of communion in Biblical Christian churches.
There are no “other Christ’s” as your Latin phrase indicates.
Only One, Jesus.
Invite the Holy Spirit to help.
The steps taken in the Catholic church are not needed to properly celebrate the Lord’s supper, but I know it is tradition.
“Christ cannot be there to change the bread and wine into his Body and Blood as he did at the Last Supper.”
Maybe the Christ you follow can’t do it, but the one I know can do pretty much whatever he pleases, since he is Lord of Heaven and Earth. He’s not imprisoned up in heaven unable to participate, instead, anywhere two or three of His follower gather, He is there too, whether one of those followers is a priest or not.