Look at your description, you also have buddies who know how to train, and they are right.

The soreness is more caused by lactic acid accumulation, but your muscles won't feel the wrong amount of training until the next day. Fitness must be gradual, there is no such training. Once you relax after such training, you will bounce back quite quickly.

Personally, I think you need to adjust the amount of training, not to mention not hurting muscles but only joints and tendons. Dumbbell training itself is a complete process, not a single one.