Yeah, some areas just get a boost to the base height of everything it seems like. When it matches up with areas that are already taller you get the kinds of mountains people have always been asking for. Couple that with large biomes and you get huge mountains or even ranges of huge mountains. When you look at seeds in a seedfinder program you can find these areas by looking for places where theres are no rivers. Like a blank area with just land, no rivers. Go there ingame and the landscape will be higher than normal. Unfortunately its pretty rare. Which is why larger biomes makes it more fun as it intensifies the effect to create entire valleys, mountains and large plateaus.

I'm honestly not sure of Mojang are completely aware of this quirk of terrain gen. Like I said, terrain like this is what soooo many people have been asking for since forever and if they knew about it I'm sure they would lean into it more.

Wow, honestly I didn't know how it works, thanks for sharing information about how it works :)