What a beautiful aquarium, honestly amazingly beautiful :)
From photos it appears you have alot of light/natural light from windows indirect/direct light which will contribute to the growth of GHA. Your aquarium lights may be contributing aswell
From your photos the GHA is too long for any clean up crew to manage (they will not eat it)
I would certainly avoid any additional chemicals to combat this (in my opinion)
In my opinion.. it will require hands in removing, it's a very large aquarium, the tooth brush is a great tool (on small aquariums)
For this size aquarium I would use a 'bottle scrubber' but I would only use in sections (to remove the longest GHA)
Then gradually work across all.
One section at a time every week