I felt the same way, i tried to use clip white/black back and forth but the detail just wouldn’t comeback.the person in the video is moving the sword too fast so sometimes when it blurs out it’s not a big problem if the sword is not visible. My friend told me to try primatte keyer which didnt really make any difference though it did make it easy to remove some of the bright which eventually ended up removing some of the detail on the guy’s Torso which matches the color of the bright spot which turns yellow-ish after keying it out.
I thought of using roto brush to which does a fine job apart from few areas where around the sword it just can’t find pixels for the sword to mask around.


I also tried to mask out video in two halves so i can key out seperately
meaning, i tried to key out the bright spot seperately after creating a rectangular mask so it doesn’t effect the guy or his uniform etc.
still same 🙂