What is the meaning of Romans 1:21?

* The two F.O.G. Bibles & Commentary below are currently a work in progress.

For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.

Berean Standard Bible (BSB)

Because, knowing God, they didn’t glorify him as God, neither gave thanks, but became vain in their reasoning, and their senseless heart was darkened.

World English Bible (WEB)

Because{G1360} that, when they knew{G1097}{(G5631)} God{G2316}, they glorified{G1392}{(G5656)} him not{G3756} as{G5613} God{G2316}, neither{G2228} were thankful{G2168}{(G5656)}; but{G235} became vain{G3154}{(G5681)} in{G1722} their{G846} imaginations{G1261}, and{G2532} their{G846} foolish{G801} heart{G2588} was darkened{G4654}{(G5681)}.

Strong's King James

(21) Because even though they understand The אֱלֹהִים Elohim-God, they don't glorify Him as יהוה YAHWEH, or give thanks, rather they render it futile in their thoughts and their foolish hearts darkened.

The F.O.G*

[21] Despite knowing about God, they refused to honor Him as God or express gratitude to Him. Instead, their thinking became futile and their foolish hearts were plunged into spiritual darkness.

The F.O.G Paraphrase

because, having known God they did not glorify Him as God, nor gave thanks, but were made vain in their reasonings, and their unintelligent heart was darkened,

Young's Literal Translation