The second day is purposefully a low-volume, low-rep, ‘technique practice at high load’ strength focus day. It’s natural to not feel as challenged. Remember, the goal is not to hit the gym and hammer yourself as hard as you can every time. This will compromise recovery. Your goal is to deliver the right amount of training stimulus needed to get stronger and grow, then allow that to happen by eating well and sleeping well. Resist the temptation to always do more.