Are you familiar with MYOG - Make Your Own Gear. Its a whole thing.
Its the bro-ier end of the sewing world for people who want to make their own camping gear. There are technical fabrics with names like 2.2oz HEX70 XL, intense abbreviations (UHMWPE is a ultra-high-molecular-weight-polyethylene, of course) and conversations about the ideal thread/fabric/needle combination. Rather different than the conversations around quilting or garment sewing, where the more technical conversations sound like “Will this shrink when I wash it?”
I have fallen down this rabbit hole before, but this is the first time I have actually started making my own gear. And at this point, its pretty simple stuff sacks and zipper pouches, along with pretty simple modifications to gear we already own - adding velcro to a pocket that sags, replacing a broken buckle, and reinforcing seams.

And as for fabric, I have been harvesting fabric from a broken beach shelter and an old tent which I thought we had gotten rid of years ago when we got rid of it’s broken poles and ripped rainfly. But no, its been taking up a whole tub in our basement for 8 years. Great use of space. And now I am eyeing a kid’s windbreaker that is in the donation pile, but its a great shade of orange…

A few excellent resources:
Roll-top stuff sack pattern generator
Round-bottom, cinch stuff sack pattern generator
LearnMYOG also has a zipper pouch and boxy stuff sack pattern generator
Ripstop By The Roll also has a library of resources and a number of pre-cut kits.
MYOG Subreddit