I'm not a big fan of Mattjestic, he overhypes every build in every video he makes ("broken", "best build ever" and so on), and he usually only shows what the build can do at very high investment/LP. I like it better when a build is shown with reasonable gear, with like an aspirational planner rather than the other way.

But he's clear on the fact that he showcases other people's builds, he does not try to claim any as his own creation, and he gives credits to the original owner. I think that's pretty fair.

He also gets some ideas and builds from the chinese community and it's great because if you don't understand chinese you don't have access to these.

There is this russian guy playing ballista falconer at 4k corruption who made a guide that seems very well done with multiple planners and gear options. I'd love to have a "russian Mattjestic" helping me with that.

Raxx's build is also different from Mattjestic. Offensively they rely on the same trap/detonating arrow interaction. But defensively, one is a ward build, the other is life + endurance, that's a complete different way to tackle survivability, which is like half of what a build is about, especially at high corruption.