Okay, I will call out one product hailed as "universally accurate" in every gun they try, this is the FX Hybrid slugs. (maybe not fair to say universally friendly, but this is implied.) Also, FX Hybrids cost a "fortune" compared to some other slugs on the market, so the implied should be there with the price.
What I would LOVE to see is a real brand to brand comparison and see how truly accurate the Hybrids are in the different brands. I.e. Edgun / FX / Taipan / Kalibgrun / Daystate & Brocock and so on. The Hybrids are supposed to friendly for pellet designed barrels, or barrels leaning that way, and so no slug barrels allowed in testing. Or any ammunition.
There could be say one of the "big YouTuber names" and I mean this in plural, get together and compare some major brands in say two of the most common calibers, and longest the Hybrids have been around for, .22 cal and 25 cal. Each brand will have a couple of different models for each caliber. And do different Tier guns. Budget to "elite".
Each "brand youtuber" could keep each other honest for the review and no cherry picking groups. Each gun gets 5x10 shot groups at 25, 50, 75 and 100 yards. The guns have to be out of the box new and not customized for the Hybrids. Each company gets 3 models two chosen by them and one chosen by an opposing group, and how groups are paired is chosen randomly. Also, each group gets to shoot the other group's guns.
I can go on and on about the testing model I started above, but it would be interesting to see if companies are brave enough to do side by side comparisons. Everyone watching over over everyone else's should will keep things "honest". Yeah I am probably off base, but it would be interesting to see, IMHO.