In one of his parables (Matthew 13:42) Jesus said that the wicked were to be thrown into a fiery furnace. In two others (Matthew 22:13, Matthew 25:30) they were to be cast into outer darkness, and in another parable (Matthew 24:51) they were to be cut in pieces. It seems likely, then, as you suggest, that these are figurative expressions for destruction.
In Mark 9:48 Jesus says to beware of hell, “where the fire is not quenched”, which could be considered to be a literal fire, but the same verse says it is “where their worm does not die”. It is most unlikely that this means everlasting fires and immortal worms, and much more likely that it is a figurative expression describing the destruction that occurs in a rubbish tip.
In Revelation 20:10 we are told that the opponents of God are to be thrown into the lake of fire, but in verse 14 of the same chapter that Death and Hades are to be thrown into the lake of fire. It is clear in this case that the fire symbolizes destruction.
Although fire is often used symbolically in this way, it is possible that God will literally use fire to destroy the wicked. For example, 2 Peter 3 contrasts destruction by water in the Flood with destruction by fire when Jesus returns:
… the world that then existed was deluged with water and perished. But by the same word the heavens and earth that now exist are stored up for fire, being kept until the day of judgment and destruction of the ungodly. (2 Peter 3:6-7)