Lfa

Hello, I am 17 years old have been on the gym for about 5 months, I love it and can already see some good progress, however, my training is upper and lower, and when I train upper I have a lot of exercises to do meaning I have to stay in the gym for like 2 and half hours wich I feel like is a lot of time. If I don’t train all the upper exercises I feel like i might be losing gains and not pushing myself enough, can anyone help on how to organize my workouts and if I should reduce the number of exercises( if I do reduce would I be training some muscles less?)