The iron from Primitive Technology is maybe enough for a small piece of jewelry like a ring, and that's from many runs of very time consuming and labor intensive smelting. I'm not a metallurgist, but it also looks pretty bad. Even if it was modern tool steel with no impurities, 20g of iron pellets is pretty useless if you don't have a forge.
Your knowledge and skills are impressive, but I very much doubt that's common, and you most likely use modern tools to build houses. I'd be surprised if you could build better houses with sticks and stones than the stone age people who have been doing it for generations.
I've seen videos of people who make paper traditionally, and I remember that knowing the basics of it is about as useful as knowing the basics of making a rocket. Unless you have actually made paper and gun powder from scratch without any modern tools, I will not believe that you could do it.
I have to agree with you regarding writing and math. Also social sciences like philosophy, ethics, psychology, education, etc. Any tool you can use with only your brain would be be very helpful.
But I think the biggest issue would be convincing people to try new things. For all I know, photovoltaik could be a gift from a time traveller, but there was (and is) much opposition to it because many people are so conservative. If you started explaining electricity to people in the stone age, I wouldn't be surprised if you'd be banned or worse.