Assistance exercises are fantastic for isolating specific muscles, they should not however be the focus of your strength training workout. You do of course want to become stronger in the assistance exercises as they will benefit your overall lift in many ways, but do remember they are only an ASSISTANT exercise, the main lift is the end is most important aspect.
No one likes to train weak points, however if you don’t train them you will never be able to reach your full potential. For example if your weak point is pulling off the ground then you should be incorporating deficit deadlifts into your routine, by no means are they enjoyable but they will take your deadlifts to new levels. Another example, if your weak point is the lockout, then incorporate rack pulls into your training… Struggling with grip? Incorporate farmers walks into your routine and so on. Having a well rounded lift will skyrocket your results.
Note: Not addressing weak points can also lead to injury later on during your training.
The Deload Phase is essential in strength training, it can be referred to as "active recovery" as it allows you to still train whilst ensuring your body recovers properly. A Deload phase is basically a period of lower volume (fewer exercises and/or sets) and intensity (lighter loads). A fairly standard rule of thumb is to train 70 percent of the total sets you normally would do when deloading. As for weight, look to lift around 70-80 percent of your standard.