In the vanilla game, structures follow a certain formula to determine stability, and is not at all the same as real life would be.

A good basic overall guide to building "rules" watch the following video.

https://www.youtube.com/watch?v=gD3YQGufXgA&t=505s

Yeah, it has nothing to do with real world physics and supports and everything to do in how many build pieces you've used from the ground up.

Different poles "transmit" better from the ground, allowing you to build higher. For example a Core Wood Pole lets you build more pieces vertical when you attach things to it.

it is all about the distance (in build pieces) from the ground to the top of your roof.

Without pictures, nobody can give you 100% solid answers, just general advice, but there are some fantastic builders here, who I'm sure can look at a few pics of your base and tell you exactly how to make it work.