If you have an army of moschops, put them on wander around an area with lots of bushes and you’ll have plenty of fiber and mejoberries. It will save you some time for trying to tame a therizinosaur to gather fiber.
This guy is my favorite dino to start. It can farm LOTS of fiber, chitin, berries, rare mushrooms, rare flowers, polymer, etc. And it has a considerably good melee and health. But people don't see its value just because its a big coward iguana... Lmao. But for real, they're really one of the best dinos to get at the beginning, if not the best. Give this an up to let people know.
If you want to use these to collect fiber on mobile you need to set them to wander and use the whistle to get them to stop following you. I personally let my Moschop out of my base to wander and collect fiber while I stay near it collecting stone and wood. They will also occasionally take down trees for you and eat corpses.
Moschops is literally one of the best chitin and polymer farmers, if not the best. Kill trilobites with it and you'll see how much chitin it gets (and a bit of oil and pearls too). I spent the last hour killing trilobites with Potato (my Moschops) and got two chests full of chitin. Apparently people don't know this so give it an up to let everyone know.