Matthew 25:46 clearly says the wicked will have everlasting punishment, and the saved will have everlasting/eternal life. That’s pretty clear.

If one believes scripture, it says heaven is eternal, as is hell.

“And there shall be no night there, and they need no candle, neither light of the sun; the Lord God giveth the them light: and they shall reign forever and ever.” Rev 22:5

If believers have eternal life, rejecters of Jesus have eternal death (fire). 2 Thess 1:8-9 and Jude 7 mention eternal destruction.

Rejecting Jesus is a horrible eternal sin that requires eternal punishment.

It is so easy to be saved and avoid eternal hell. Just believe on the Lord Jesus Christ, and you will be saved.
Acts 16:31