Every lifter owns one lift that refuses to move while everything else climbs. Usually the problem is not effort but aim: the weak point needs to be found, named and trained on purpose.
Find the exact point where the lift stalls
Film your next few heavy sets from the side and watch where the bar slows down. On a bench press it is often just off the chest; in a squat, halfway up or in the bottom; on a deadlift, at the knees or at the very top.
"My bench is weak" is too vague to train. "The bar dies five centimetres off my chest" is a problem with an address, and problems with addresses can be visited.
Check whether it is strength or technique
Many sticking points are setup problems in disguise. A squat that pitches forward may be loose bracing; a bench that stalls off the chest may have no leg drive behind it at all.
Test it: drop to a comfortable weight, film again and compare. If the bar path still wobbles when the load is easy, spend a few weeks on technique with practice sets before buying any weak-point theory. Often it is a mix of both, but technique problems cost nothing to fix, so rule them out first.
Choose one accessory that attacks it
Match the exercise to the stall. Pause reps at the sticking point build strength exactly there: paused bench presses for the chest, three-second squats out of the bottom, heavy dumbbell rows for an upper back that gives up before the legs do.
One accessory, chosen well, beats five chosen at random. Pick the one that loads the exact range where the bar slows down, and leave the rest of the program alone.
Add it without wrecking your recovery
Two or three sets of the accessory, twice a week, straight after the main lift. It should feel like precise work, not a second workout: if it leaves you sore for three days, it is stealing recovery from the lift you are trying to save.
Slot it on your two easiest days of the week so it never competes with a heavy session for recovery.
Keep the load moderate and the technique immaculate. The accessory exists to feed the main lift, so it never needs to be impressive on its own.
Give it eight weeks, then re-test
Weak points move slowly, so commit to two months before judging. Keep the accessory in place while the main lift keeps its usual spot in the week.
Then re-film the same way you filmed at the start and compare the two. Bulky keeps your notes with every logged session, so write down where the bar stalled each week — when the sticking point is gone, retire the accessory and go hunting for the next one.