King James Version
For thus saith the LORD; David shall never want a man to sit upon the throne of the house of Israel;
New American Standard Version
"For thus says the LORD, 'David shall never lack a man to sit on the throne of the house of Israel;
Holman Christian Standard Version
For this is what the LORD says: David will never fail to have a man sitting on the throne of the house of Israel.
https://www.studylight.org/interlinear-bible/jeremiah/33-17.html
It seems plain to me the way it's stated.
David's throne will be occupied continually.
Comparing translations is the approach of one who has basically remained a novice - no matter how much time he or she has been "studying the Bible."
1 Corinthians 3:1 And I, brethren, could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ. 3:2 I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.
Hebrews 5:12 For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. 5:13 For every one that useth milk is unskilful in the word of righteousness: for he is a babe. 5:14 But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.
Nevertheless, Romans 5:8