How to change up my workout routine? I think i hit a plateau.

[NJminute]

whats up guys, i need some help. my and some people were have a conversation about weight training, and one of them said that you have to change up your workout from time to time because your body gets used to the routine if you do the same thing for long. how can somebody change their workout? here is my routine.
for each exercise, i do 3-4 sets for 8-15 reps for as heavy as i can go. currently cutting.

monday-chest/triceps
flat barbell bench press, inclined barbell bench press, pec flies, tricep pushdown, dips

tuesday- back/biceps
seated cable row, t-bar row, lat pulldowns (wide grip then close grip), deadlift, preacher curls

Wednesday-legs
squats, leg extensions, calf extensions

thursday-off

friday- shoulders and arms
seated shoulder press, lateral raises, front raises, barbell shrugs, bicep curls, reverse bicep curls, tricep pushdowns, dips.

sat/sun- off.

please help me change my routine so i can keep making GAINSZZZ!

[dday39]

many people don't know a damn thing about weight training
you do not have to change up your workout from time to time (muscle confusion is broscience 101)
there are probably better ways for you to train

[bevans100fitnes]

Focus less on # of sets, focus more on weight/reps progression

If volume were that high, as it is, I would do less sets per exercise and more exercises (for the same total volume)

Don't have time to write you an entire routine.

If you are relatively new at this, doubling your protein intake will probably break the plateau better than routine changes.
(I'm assuming your new because you're asking a very general question, without enough background info to give a precise answer, forgive me if im wrong)