Derrick Henry was the wrong example for you to use. He led the Titans to 4 playoff appearances in 7 years with freaking Marcus Mariotta and Ryan Tannehill at QB. They won 3 games after he left.
Barkley had his best season in 2022 and helped Daniel Jones look average enough to land a big contract. As soon as Barkley left the wheels completely fell off and Jones got cut mid-season. They won 3 games after he left.