Well, @
Veloist, here is my take on this.
A manual transmission is not a precision made piece of machinery.
Many need to be "broken in" before all the parts get to know and work well with each other.
Some are smoother that others, right out of the box.
Since your car has only 28 miles on it, I suggest that you drive it for a few hundred miles and see if it doesn't smooth out.
As far as shifting, here are my thoughts:
I would suggest that when shifting, wind up the last gear pretty tight (>4,000 rpms) before shifting into the next higher gear.
Also, when shifting from 1st to 2nd, pull the shift lever slowly and firmly into 2nd gear ....... same for 2-3 (except push it .....
).
It's not a toggle switch ..... the lever is moving heavy transmission parts.
I suggest you NOT "lazy leg" it .... push the clutch pedal all the way to the floor.
Hey, it's under warranty ..... so, you have time to give it a chance to smooth out.
humfrz