I have a few items from Arms of Andes that are really great. Highly recommend.
I ran into a similar situation as you after wearing synthetic clothing at the gym. It led me to create unwraplife.co as a database for plastic free clothing (no kickbacks here or anything shady, just a database).
I'm collecting a list of companies that seem to fit the qualifications, but am unclear on if they do. Have already started reaching out to those to confirm.
On point #2, the mission (https://www.plasticfreeindex.com/about) is to focus on plastic's impact on human health not environmental. Although I agree the impact of plastics on the planet is important, I want to bring awareness to the major impact it is having on humans.
Had a major flare up of RA after a particularly stressful moment in life. Went to doctor who prescribed steroid lotion - a non starter.
After research and some trial and error what solved it fairly quickly were high doses of extremely high quality fish oil (DHA & EPA) and an overall cleaner diet with less low quality gluten.
As for the "spots" sunlight seemed to be the best disinfectant to the point where now if there is any flare up I just get a nice tan and they go away.
I have no scientific basis for any of this so DYOR.