I’m a bit puzzled that you find the idea of unending torment in Isaiah 66:24.

Same here. Hyperbolic images of destruction are not foreign to Isaiah.

For the LORD has a day of vengeance, a year of recompense for the cause of Zion. And the streams of Edom shall be turned into pitch, and her soil into sulfur; her land shall become burning pitch. Night and day it shall not be quenched; its smoke shall go up forever [LXX reads literally, “into the age”; cf. Rev 14:11]. From generation to generation it shall lie waste; none shall pass through it forever and ever. But the hawk and the porcupine shall possess it, the owl and the raven shall dwell in it. He shall stretch the line of confusion over it, and the plumb line of emptiness. Its nobles—there is no one there to call it a kingdom, and all its princes shall be nothing. Thorns shall grow over its strongholds, nettles and thistles in its fortresses. It shall be the haunt of jackals, an abode for ostriches. And wild animals shall meet with hyenas; the wild goat [śa‛iyr, i.e. he-goat or satryr; in the LXX daimonia, i.e. demon] shall cry to his fellow; indeed, there the night bird [liyliyth, Lilith] settles and finds for herself a resting place. There the owl nests and lays and hatches and gathers her young in her shadow; indeed, there the hawks are gathered, each one with her mate. Seek and read from the book of the LORD: Not one of these shall be missing; none shall be without her mate. For the mouth of the LORD has commanded, and his Spirit has gathered them. He has cast the lot for them; his hand has portioned it out to them with the line; they shall possess it forever; from generation to generation they shall dwell in it” (Isa 34:8-17).

Here Isaiah describes the destruction of Edom, an event within history. He describes smoke ascending into the age, wild beasts and demons passing into the land, keeping the land desolate so that no one else will ever pass it into it. But this is all pure hyperbole. Obviously smoke is not still ascending up into the air somewhere in the middle east to this day. Plus, these images are not of torment, but of destruction. The lasting effects of the destruction are signs of God’s judgments to the rest of the world. I’d suggest Isaiah has something similar in mind when he describes the dead corpses being consumed by fire and worm.

By the way, was not Isa 66:24 fulfilled within history, even before 70 C.E.?