Seems like you are into strength training, yet you follow a bodybuilding split routing.
Taking PWO won't make you feel more motivated, just more cracked out.
I'm into powerlifting (a few years older than you). What worked for me:
Changing it up - the programs I've tried over the years: 5x5, Madcow, Smolov Jr, Wendler, 10x3 bench. Change is good, keeps you entertained.
Making short/long term goals - long term goals for me were to hit 5 plates on dl, 4 plates on squat, and 2.5 on bench by the end of year. Short term were to switch to hook grip instead of mixed on dl and focus more on front squats. Achieving these goals keeps you motivated. And yet failing (I went for 405 on squat yesterday and got buried) also humbles you and let's you improve on your weak points.
Getting a visual of your progress - if you don't own those already, invest in measuring tape, scale, pen and paper, a good tracking app, etc. If you are trying to lose/gain weight, get on that scale daily. If you wanna have bigger arms/chest, measure them periodically. If you are strength-training, record your results so you could calculate the poundages. All this can give you an idea of whether or not you are progressing.
Watch videos on youtube - there are plenty of channels that carry great info. If it's my squat day, I'll watch some videos of people squatting heavy with perfect technique. Motivates me.