Here’s the 2022-23 FAFSA formula, not sure it’s final though.
$27K is upper income limit for auto zero EFC, and $49,999 parental income is the upper limit to qualify for simplified EFC calc.
Is your kid’s 529 plan an Individual plan? This is set up with you as the account owner and kid as the beneficiary. Or is the 529 plan a custodial plan, where the kid is the owner but because they are minor the plan needs an adult custodian?
The first type is by far the most common, and parent will report that on fafsa as their asset, subject to $10K asset allowance and then assessed at 5.64% for EFC purposes.
You can also run the fafsa forecaster here: Net Price Calculator