you sprained your wrist during what exercise ? might want to fix the form or the way you grip the bar?

also straps and wrap is different thing, you hardly need wrist wrap unless you are pressing a huge amount of weight, or low bar squatting heavy

this, i know why, when you're spinning the weight, on the way up, you're suppose to control it, slowly

if you spin too fast, it will create a rotation from the momentum of the dumbbell hence spraining your wrist

Arnold concentrated on hypertrophy so everything should be controlled, time under tension

i've never used a wrist wrap, but looking at the way wrist wrap wraps your wrist, i dont think it can help stopping the momentum from rotation.

for deloading, some prefer to do a scheduled deload, some do it when necessary.

i usually just schedule my deload week near exam or assignment deadline since i will not have energy to go all out either might as well deload to refresh both my mind and body.

usually you deload by doing the same sets and reps and exercise, but dropping the weight to somewhere you feel comfortable, no struggling, usually about 60%

or

drop the sets but going with the same weight you normally train

or

do some fun lift that you've never done before, like replacing benchpress with weighted push ups, or replacing pull ups with pull down or do some burpess or cardio etc...

Yes you need straps for pulling and wraps for pushing
That is provided your grip starts to give up during pulling and wrist giving up during pushing
But that is not the best way to overcome this problem
You might want to consider start training forearm and grips
Whats more sexy than having veiny forearm, your biceps and all gets covered by shirt also right, but forearm didnt

of course, and that is why people keep on saying no thumbless grip during benchpress because it will fall easily