I applaud your desire to stay with natural fibers and to protect the environment.
I don't want to use CF to advertise any clothing manufacturers, but when I google "modest clothing for women", I get a reasonable number of hits, some of which are made from cotton or linen. Most are made from dyed cloth, so if you want undyed cotton or linen, admittedly that's going to be a harder search.
I don't pay attention to the clothing promotions on social media, so I can't help you there.
If you really don't like any clothing you see in stores, could you learn to sew your own clothing? My mother sewed most of her own clothes, and two of my children sew some of their own clothes as well. (I'm afraid the sewing gene skipped a generation with me.

) Finding undyed cotton is going to be a challenge, so you might have to compromise there, but otherwise it lets you pick your own style, sleeve and skirt length, close vs loose fit, and so on. Also, if you're worried about competing with people on YouTube, your handmade garment would be one of a kind.
No, sewing is not an option for me.. i'd need an old school sewing machine from the 1800s.
The newer ones are too intricate, and go too fast. That house wifery skill skipped over me. That's not how I'm good with my hands. Although I can sort of, sew by hand. Which would take too long, and the stitches probably wouldn't last.
I've found some options of Organic cotton, and low impact dyed clothing options, but they just come in joggers, and t shirts & hoodies. I bought these sheer, head coverings
And then I drape them over my shoulders, as more like a scarf
And then it adds, almost femininity to it. They're affordable, and they're Orthodox
Then I add an Orthodox beaded bracelet, with a cross around my wrist, and my medical ID alert necklace..
All of this stuff is expensive
They sometimes have dresses on those shopping networks on tv, with sleeves that are mostly cotton, but I had a dress from a particular place from modli .co.
I have learned, over time that no matter how much my wardrobe, and the laundry starts to bother me, To keep what I really like if I find it
Because department stores
Have been put out of business,
And you can never buy the same thing again!
I lost, alot of my clothes the last time I was hospitalized. My mom says she stays up to date, but she's never up to date.
There really is no need to bring you clothes in the hospitals, anymore..
They gifted us a sweatshirt when it got cold, and they give you new scrubz when you shower now.
She brought me so many clothes, and I lost a few in the hospital.
So, it gets annoying storing a wardrobe. But, when I find a piece I want, I need to learn to keep it because it will sell out, and they'll never sell it again.
And the fabrics are never gonna be perfect.
There's only one place that sells low impact, or dye free cotton & it's gonna take me slow time to get stocked up on it.