Hi there, and Welcome to YT
Little Derby is adorable. He looks 100% yorkie puppy to me . Many yorkie pups have floppy ears. Especially during the teething stage. Sometimes, one ear will go up , and the other ear will stays down.
my female Yorkie , as a little puppy always had floppy ears. Until she had her first grooming apt. The groomer shaved 2/3 of the outter ear hair, and also any hair growing inside the ear canal , he plucked out. Becasue the hair keeps growing inside the ear. groomers use ear powder to do this, I have not ever tried to do it on my own. Also around the edges of the ear , he clipped the hair too.
When I picked Suzi up, her ears were standing completely straight up
She has not ever had a problem since.