I just watched your video. On my phone so not the greatest view or sound quality.
It does seem like a lot of wrist slap.
Like Paul suggested maybe raise your brace height
Also it looked like when you notched your arrow it was fairly close to center shot. (Remember I’m just looking on my phone.
A wide handle doesn’t necessarily mean you need a weaker spine if your string alignment is not centered.
If you put an arrow notched at same point, but opposite side of handle does it look further from center shot?
That’s sometimes how I test my string alignment.
Your arrow spine might be correct, but the string alignment might be a problem for wrist slap.
Still a pretty bow Thomas. Sure hope you can figure it out.
Bjrogg
It is fairly close to center shot, because with all the bends, the string is off center toward the right side of the handle. Does that make sense? This photo exaggerates it because it's hanging on an arrow, but gives you a pretty good idea.

In your case you said the bow has some twist. This can give you some trouble so you need to verify your grip position. Hold the bow loosely in your bow hand, pull it back several inches and then grip it hard. Now look and see if it is in the same position you would normally hold it. Just a little bit off here can affect your spine and the handshock and this would be my biggest suspicion for this particular bow.
Not sure I'm following you, here, Badger. Please clarify what I'd be looking for. Do you suspect the handle is torquing and throwing off my grip?
I did raise the brace height to 6". It helped a little. I also tried putting a few 650 grain arrows through it last night. It was a lot quieter, and I was able to read a magazine while I waited for the arrows to arrive at the target.

Anyway...here's what I think I'll do.
1. Put this thing back on the tillering tree and see if the tiller has gone wonky for some reason. Several people think it sounds like the limbs are out of sync.
2. Try Badger's grip/twist suggestion, if he can get through my thick skull what he's getting at.
3. Keep trying to modify my form so the string isn't slapping my wrist.