If you'd been struggling with a problem, and finally found a resolution, you'd probably say, "What a relief, man!" Or you could say, "I'm so relieved to have that problem finally solved, man."
Relief is a noun.
Relieved is a verb in the past tense.
You would only use "release" if you had some sort of built-up stress or energy that you needed to get rid of. Then you might say, "Every day after work, I go to the gym and walk three miles on the treadmill. That's my release, man."
By the way, "man" is a common interjection used by people of all races, not just African-Americans.
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