Hello! As a starting GFX designer I must say you are doing a pretty good job at it! The first GFX you have showcased looks remarkable, But I do think the sun ray on top (orange/red one) doesn’t quite fit in so good, If you can change it like the other ray (white/gray) it would fit in more. That is just my opinion though. The star wars GFX looks pretty good too, The lighting fits perfect with it. There isn’t much more for me to say on that. And the last one is a pretty good group logo, it is just a bit basic. I hope I’ve helped you out, and continue doing GFX because I can tell you will be amazing at it!
Nice GFX, I’m not sure if you do but I recommend using a rig, Also try play around with different lighting. One thing I noticed is the face looked quite pixelated on the second one