Invest in a logo-free, full-grain leather briefcase that improves with age....

https://rapid-wiki.win/index.php/Why_Does_My_Laptop_Slide_Around_Inside_My_Briefcase%3F

Invest in a logo-free, full-grain leather briefcase that improves with age. Ensure the zippers are YKK, and check that it fits your 15.6-inch laptop securely