It isn't "bricked", it is just an incorrect fusee count that is stopping it from booting. Put it into RCM and then push atmosphere to it. Update it back to 8.0.0, just like how you downgraded it, so to match the Fusee count.
After doing this you should be able to boot back into HOS and be able to use your switch normally.
I would recommend making a nand backup with hekate first, just to avoid any
actual bricks.
(With a nand backup it is almost impossible to brick your switch, unless you break it hardware-wise!
)