Correct. The appearance is here to indicate the real Eucharistic presence specifically of Christ, apart from the ordinary omnipresence of God.
The only place where Christ’s blood was offered was in heaven. (Hebrews 9:12)
"By his own blood, entered once into the holies, having obtained eternal redemption." Indeed. Ther Eucharist is not a separate sacrifice but that very sacrifice described in Hebrews 9, applied to us personally.
You seem to have overlooked or misunderstand what “once” means.
Unlike the Jewish high priest, Christ heavenly offering obtained “eternal redemption” and did not need to be repeated or performed on earth.
It was offered and accepted “once”.