Review on 🔧 Enhance Arduino Mega Prototyping: KEYESTUDIO MEGA Prototype Shield V3 Board with Breadboard, Ideal for Circuit Building Projects by Joshua Mejia

Usually when making a prototype board like this they used a stacking header so the pins go to the end of the Arduino and allows you to stack. This leaves an extra set of pins open for each connection to be soldered. In this case you will have to use Dupont connectors to access the pins as they both used sets of pins. I'm sure it's fine for a one-off test project, but since I'm making a product for humans, everything needs to be soldered.