What are my training suggestions for upper traps?
Shrug variations are going to be your ideal training motions for the upper traps. Since the upper traps do not attach to the scapula or the humerus, and their function is to raise the shoulder up and slightly back by rotating the clavicle at the joint where your clavicle meets your sternum (sternoclavicular joint).
Exercises that will be limited by the shoulder torque wouldn’t be your best choice for hypertrophy, for example, lateral raises, low to high rows, etc. These exercises will still work the upper traps to various degrees so they should be considered in regards to total volume. But, you wouldn’t use them if your goal was specifically upper trap stimulus.
Another important consideration is how much loading you are getting from heavy pulls. Perhaps even more important that accounting for things like lateral raises , low to high rows, and overhead movements is exercises like deadlifts, trap bar deadlifts (it’s in the name lol), RDL’s, and any other exercises where the traps are isometrically holding alot of load in a relative lengthened position. These exercises are likely to contribute to more overall stimulus and fatigue in the traps than your DB lateral raises for example.
To be honest, for many people they don’t need to directly train their traps because of how much overlapping volume they get through training the rest of their body. In some cases for female competitors we actually have to make exercise selection decisions to intentionally reduce the volume or trap volume that they are getting in their lower body exercises.