my iPhone is not showing up on finder on Catalina OS

See "Sync or Remove Content Using the Finder" here.

Use the Finder to sync your iPhone, iPad, or iPod with your computer - Apple Support

If that fails:

If your computer doesn't recognize your iPhone, iPad, or iPod - Apple Support

catalinaOS wrote:

1) it is new, maybe it was a version from previously in the year or end of last year

MacOS Catalina was released October 7, 2019. Apple sells new Macs in factory sealed boxes with the then-current operating system at the time of manufacture.

catalinaOS wrote:

I just purchased a new MacBook Pro. Got it turned on, updated to CatalinaOS

Since it was new, surely it came out of the box with MacOS Catalina. So I wonder why you said this.