SilverwingVFX shows some modeling tips for building a ketchup bottle in Ciema 4D using Subdivision Surfaces.

This new tutorial from SilverwingfVFX (Raphael Rau) departs from the others. While Rau often covers rendering and lookdev stuff, this new tutorial dives into creating a ketchup bottle (a complex form to make) in Cinema 4D using subdivision surface modeling techniques.

Also of note is this tutorial from Polygon Pen, which shows a simple subdivision modeling workflow for creating the complex rigid and soft forms of a typical detergent bottle. Visit that tutorial here.