I also have the feeling that most 3rd party presets sound bad on my guitar. In particular the high gain tones, not the cleans. It is like they have too much fizz at the high frequencies. I call it "can of bees syndrome"
It could be that they have lost hearing at the high frequencies, so they do not notice, or that they do not play with their head right in front of their monitors/speaker, or that their monitors are not truly FRFR, or that I am too sensitive to these frequencies, or just different tastes.
Normally I do not cut the high frequencies, because then it sounds muddy. For me it is a question of finding the right IR with the mike in a sweet spot (normally excluding the nasty SM57)
I'm always thinking just that any preset is based so fundamentally on how the character of an IR melds with how a particular pickup on a particular guitar with a particular setup, with a particular pick attack, etc. And I think it can line up really well for two players with pretty similar guitars. Like, I'll look at a Leon Todd video, where he's not trying to sell you a preset, but doing the awesome thing of showing how to use the Axe in different ways, walks you through his creation, posts his preset, and gives you his IR...and I try that preset, untweaked, playing the same thing he plays in the videos, and it sounds like garbage mixed with crap mixed with trash mixed with refuse, on a shit sandwich. And then I realize, "Oh, yeah, I'm not playing his guitar, and I don't hold my pick like he does, etc. If he played one of my presets on the guitar he's using in this video, it would also sound terrible." And that totally makes sense to me. I remember one of his where I had to boost my input insanely to get anywhere close to what he was getting, and still the EQ of the guitar was just bad with his settings. On the other hand, if he took that particular guitar and played through one my presets, it would massively overload and probably sound like the most biting harsh thing on top of being an unintelligible mess. Especially because I really favor these Saturday Night Specials, which are pretty low output, they can sound really weak on a preset made for powerful pickups, or they'll sound muddy on a preset made for a single-coil. Not to mention, my guitar has such a weird wood combination (Black Limba body with Wenge neck), I'm sure that's altering things too. Plus, the fact that my relatively low output pickups are also set very far away from the strings, and on top of that, my bridge is a Floyd. Normally a Floyd just seems to pair with high output fire breathing pickups. Mine is just a weirdo combination, but I love it haha!
We're in this new era of tone being also about audio engineering, and that's a skill all of its own. I respect great players, and I respect great audio engineers, but it's a weird thing that getting a great guitar tone with IRs gets you so into that world of engineering, much moreso than tweaking a tube amp in front of you. And for that reason, I totally understand going to others' presets, to get a feel for the engineering methods that feel right to you as a guitarist. I mean, I don't see guitar heroes of the past giving any thought to high and low pass filters to apply off the Neve console. I think, as with anything in playing, you're so much better off eventually to hone your own engineering go-to techniques, but I'm always thinking your time is better spent on being an awesome player and an awesome writer, and whatever gets you there is okay.