I don't believe your interpretation of this passage is correct, and it paints a picture of an angry, spiteful God that threatens people into submission.
The first problem, is that the truth being suppressed is in verses 19-20 is God's "eternal power and Divine nature," and not that "God is the only God."
The second is that the wrath in verse 18 is "being revealed" actively, not past or future tense. That means that whatever the wrath is was going on at the time Paul wrote it, but it was then being revealed. It was already going on. We don't have to guess at what the wrath was, either. It wasn't "God will punish you," it was "God gave them over." (vs 24, 26, 28) The wrath of God is Him allowing people to live in their own sins; it is God letting them suffer the consequences of their own decisions.
Fortunately, Paul goes on with the rest of Romans to explain what can be done about it. It's called the Gospel. We are all experiencing God's wrath to the extent we are in rebellion against Him. If we give in to the lusts of the flesh, we will experience the consequences of our actions. This isn't God punishing us, it is God letting us learn from the negative consequences of our own free will choices.
Thank you very much for the comprehensive feedback, with which I agree fully. Maybe we can also add that God is truly God, to "the eternal power and Divine nature".
If we read further to verse 32a)" Although they know God’s righteous decree and His judgment, that those who do such things deserve death,". Thus in the end if we don't repent it will lead to death.
I try to keep things as simple as possible, and hopefully don't give up the essence of what God teaches us, through His word. I however do agree with your explanation and appreciate your comment.