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It's not that the scores Credit Karma gives you aren't accurate, they are just based on a different scoring model (VantageScore 3.0 aka FAKO). Very few lenders if any use these VantageScores in their lending decisions.
You can get your 3 buraeu FICO 8 scores from Credit Check Total for a $1 trial registration; but make sure to cancel your membership within a week prior to the end of the trial period. You can also get your monthly EX FICO 8 for free from Discover even if you don't have any credit account with them (they give you TU FICO 8 if you have a credit product with them).