You’ll find a long history of speculation that Sodom and Gomorrah did indeed perish beneath the Dead Sea.
There’s little clear help from the Bible. To be sure, there are not only numerous references in Genesis; but frequent references - Deuteronomy,
Isaiah, Jeremiah: just about anything bemoaning the wicked ways of the Israelites and Hebrews.
And in the New Testament, too: Gospels, Epistles right up to Revelation.
But it’s plain that all later references merely echo Genesis and the common metaphor of the Cities of the Plain as evidence that the Lord will destroy
the sinful: usually a warning to a “lapsed” Jerusalem.
Typical, would be

euteronomy 29 “the whole land thereof [is] brimstone, and salt, [and] burning,”, or in Zephaniah:“the breeding of nettles, and
saltpits, and a perpetual desolation”
Which conveys the imagery of a wasteland with saltpits; but doesn’t really place the cities anywhere in particular.
But nothing contradicts the notion: so it can be a rewarding search.