no offense, sorry if you take it that way...........but......
that long of a brine is overkill on salmon, alot of people try to over salt / over brine a thin little piece of fish.
Just from your photos, looks like the outside of the fish is a bit dried out, once again no offense.
All depends on your final product, some salmon jerky is great, squaw candy is what it's called. I brine my smoked salmon 15 minutes to 30 minutes, an hour max, if you do it over night and with tons of onion/garlic/pepper in the brine is just overkill that "IMHO" ruins the fish. Been there over done that.......tread light, don't get an overly heavy hand on the brine or seasoning.
I'll post some photos soon to show you what I mean, and what I do.
I'm always open to new ideas, but just IMHO a brine that long will almost pickle and over cure the fish.