Do you mess with water chemistry? I do full traditional mashes/90min boils also. Got my water chemistry down so I get smooth brews out of it every time.
Also, I'm going with MUCH less hops and introducing cold in the IPAs. As you noticed, even whirlpool additions will add a lot of bitterness. Cold introduced cryo hops is my new methode to experiment with.
I generally treat for chlorine/chloramine, add calcium chloride and gypsum, and then adjust pH. Nothing too fancy.
One thing I’m finding with my very oat-y no-boils is that hops particles just seem to stay in suspension indefinitely. I’m adjusting my process to try to keep hops out of the serving keg as much as possible, since they’re not really dropping out even after weeks at serving temp.