Audioquest is bright??

I agree they probably need some break-in. Give it a couple weeks.

Another vote to allow more break in time. Some AQ Pythons I once purchased displayed a really obnoxious midrange at about 50 hours use which then disappated with extended use. Up to this experience, I was sceptical of break in claims.

my friend's experience. Extreme Clear = Extreme Unclear.

This may not be a brightness problem from the Audioquest cables but a speaker placement problem, as I have found switching cables or components require the speakers to be moved, sometimes a slight toe in or out will make a huge improvement, I find it to make more of an improvement with components than cables but try it with the cables as it does make a difference. If you still have the brightness problem you may want to try a few different brands along with IC. Another thing to do is explore the room treatment thing! Happy Listening!

this possibly shows that the previous speaker cable may have been less revealing & was perhaps covering up something else. If new, first break the replacement cables in for a good 2 to 3 weeks.
Then I might also check elsewhere to find out if the actual source of your brightness is coming from otherwise, rather than just covering it up.
Source component
AC cord
Line noise conditioner
Signal interconnect
shelving cones & footers
Right now you really don't know where you're at, & should perhaps consider some other experimentation. If all else eventually fails then I'd suspect an amp + Granite + 804 synergy issue, but not right away.