Can cosmic ghost Rider defeat Galactus?

Don’t think so. The penance stare won’t work on him.
As Galactus eats planets to sustain his own life.

Galactus had no soul so CGR can’t defeat him. Even Galactus has also cosmic powers and can easily destroy the a sun also so he can beat CGR easily.

Probably not. GR’s powers are not too strong compared to entities like Galactus. But he can stop the avengers without much trouble (individually) like Galactus. But there is a chance that he could beat Thanos with Hellfire.

Galactus doesn’t have soul .like silver surfer ,galactus have inhabited by powers of comics . because of this the gostrider can’t defeat the galactus

Nope, Galactus is too powerful for any character to defeat alone even for the CGR