en_tn_condensed/rev/17/08.md

the bottomless pit

This is an extremely deep, narrow hole. Possible meanings are 1) the pit has no bottom; it continues to go down further forever or 2) the pit is so deep that it is as if it had no bottom. See how you translated this in Revelation 9:1.

Then he will go on to destruction

The noun "destruction" can be translated with a verb. Alternate translation: "Then he will be destroyed" or "Then God will destroy him" (See: rc://en/ta/man/translate/figs-abstractnouns and rc://en/ta/man/translate/figs-activepassive)

he will go on to destruction

The certainty of what will happen in the future is spoken of as if the beast were going to it. (See: rc://en/ta/man/translate/figs-activepassive and rc://en/ta/man/translate/figs-metaphor)

those whose names have not been written

This can be stated in active form. Alternate translation: "those whose names God did not write" (See: rc://en/ta/man/translate/figs-activepassive)