Video quality better when not using zoom

Hello, i have zoom pro. i have a camera logitech brio, 4k. Window 10 on a pc. When i use the camera, the quality of the image is very clear. When i start zoom with the camera, i loose that clarity of image. Light is good however i dont have the quality of image as if i am only with the camera. I tested the image quality using recordings on cloud. i used 720 or 1080, on small group meeting without seeing a difference between the quality. I do zoom with recording. Why is the image not so good when using zoom? is this normal that i loose so much image quality?  I set the video setting to HD and the others options offered to improve the image already. i used background and it show well.  In recording, the image is stable, right, except the clarity of my face, compared to the clarity i get just using the camera. 

 I just find out that to host meetings in 720p i  need to request that in Zoom support.  But it will need to be approved.  I will wait to test my camera after i got the approval to have it in 720.  Should i assume that my image quality will be better?