I've had the Note 8, the iPhone 6 Plus, and the Galaxy S4 and S7 Actives. When I first got the S4 Active, it was a pain b/c I was coming from an iPhone 4S. It was a much bigger phone. I upgraded from it to the iPhone 6 Plus and most of the larger running belts I bought for the S4 Active worked. I did by a few more belts with bigger pouches. The Note 8 fits in all but one of my running belts and has not been annoying at all. My favorite belt is the SPI Belt with the XL pouch.
The S7 Active was actually the worst to run with because it's not HUGE but it's heavy for its size, thanks to the battery. Also, the physical keys, which I thought I'd never live without, had a way of being activated and unlocking the phone during exercise, no matter that I had all the safeguards against accidental button pushes activated. I once went for a long run and took my Active out to find I had FB messaged about 20 of my contacts a random video of a guy drinking a tropical drink at a beach bar that I have NO IDEA where it came from.
And I would add, my Note 8 IS in the Otterbox Defender case. I don't find it bulky at all. Can you tell the Active 7 scarred me?