Romans says creation makes something true about God plain: his eternal power and divine nature are displayed in what he has made. Paul is not saying creation tells the whole gospel. He is saying people are accountable because they respond to God's witness by suppressing truth and turning to idols.
Romans 1:18-23 begins Paul's case that humanity needs the gospel. The problem is not a lack of all revelation, but the rejection of the God who gives life and deserves honor and thanks.
This passage explains why Romans moves from gospel confidence to human guilt. Creation witnesses to God, but people need the saving righteousness revealed in Christ.
A careful reading should not treat Romans 1 as saying creation saves. In Paul's argument, creation reveals enough to expose idolatry, while the gospel reveals God's saving power.
Original wording based on Romans 1:18-23.
20For the invisible things of him since the creation of the world are clearly seen, being perceived through the things that are made, even his everlasting power and divinity; that they may be without excuse.