What does it Mean When it is said that Christ Descended Into Hell?

This is misunderstood and misleading expression. The King James Bible translated the Greek work ‘Hades’ by ‘Hell’ – and also translated Gehenna (the Lake of Fire) as ‘Hell’ which is very confusing.
Christ descended in the common abode of the dead called ‘Scheol’ in Hebrew and ‘Hades’ in Greek were he was seen that those who were there (or in that state).
Paradise was the place of the righteous in Hades which also had a place of darkness and bitter expectation of the final judgment (Luke 16). Hence, the power of Hades was crushed when the Light of Christ shone through its gloom and darkness. The “gates of hades” (Matthew 16) could not prevail against the one who is the Author of Life. For the first time, hades was overwhelmed and defeated, being engulfed by the Living One who has the power of indestructible life.
This is vividly commemorated in Saint John Chrysostom’s Paschal homily.
In terms of absolute personal eschatology, it can be said that no one is in Hell (Gehenna / Lake of Fire) right now.
Source: https://www.orthodoxanswers.org/what-does-it-mean-that-christ-descended-into-hell/