Saturday: squats/legs
Monday: Bench/chest
Tuesday: arms or shoulders
Wednesday: Deadlift/back
Thursday: which ever I didn't do on Tuesday, usually the one that lagged more on Monday.
Friday and Sunday: rest.
I'm not a huge fan of that weekly setup, mostly because you do triceps, then arms, then biceps (Chest/Arms/Back). So it doesn't look to give a lot of time between some pretty small muscle groups to repair and build.
What I would suggest for assistance is to do mid to high volume work with big compound movements. Nothing is going to build the muscle you want like doing heavy volume with squats/presses/rows. I obviously am not a huge fan of your weekly setup, but if it ain't broke don't fix it. This is how I setup my week:
Mon: Heavy OHP, Rep OHP, Vertical Pull, Upper Back/Rear Delts, Triceps
Tue: Rest/Conditioning
Wed: Heavy Squat/DL, Rep Squat/DL, Higher Rep Squat/DL/GM, Posterior Chain, Core
Thu: Rep Bench, Higher Rep Bench, Hor. Row, Chest, Shoulders, Biceps
Fri: Rest/Conditioning
Sat: Events (strongman)
Sun: Rest
You'll see that I do a metric f*** ton of back work each week. This is because the back can literally never be too strong. And the main reason I asked about your back work is because you want to make sure that you are doing at least as many rows as you are presses. Keeping the internal:external rotation work evened out is going to do a lot for you as far as your big 3 are concerned and as far as keeping your shoulders healthy. I would even argue that you should do
more external rotation work than internal, and this is especially true for most guys starting out because of how frequently you see guys that only do chest work throughout high school and end up with terrible muscular imbalances because of it.
For you, obviously, there wouldn't need to be an event day. And on that day you would have a secondary lower day which would again include squats AND deadlifts. Not at the same intensity level as the first day, and you would also do some more back work, and hit the quads with some unilateral lower body movements (which would also help keep your hips healthy).
But, this is how I do my training. (and most of the people I work with)
For you, I think the main takeaway is to not get too caught up in what is PLing or BBing. What you want to do to build the most volume is heavy volume work with big compound lifts after you do your main movement that addresses a weakness in your lift AND a weakness in your physique (because a weakness in your physique will also typically be a weakness in your lift as well).