There’s a big machlokes about which garment materials are chayav deoraysoh in tzitzis. Everyone agrees cotton is chayav at least derabonon, but the gaon holds that it is deoraysoh, even though we have a klal of tzemer and pishton being the Torahs definition of ‘beged’.
The mishnah berurah says one should bring themselves into a chiyuv deoraysoh when possible, and recommends wearing wool.
Yerushalmis who follow the gaon wear cotton, and in bnei brak the chazon ish held it was a chumra de’asa lidei kula to davla wear wool, because since it’s very hot, the wearing of thicker wool garments might not be considered “malbush”, and so he wore cotton and so did rav chaim kanievsky.
Synthetic fibers are a shailoh if they’re chayav at all, i.ee mesh. It’s best to avoid mesh tzitzis altogether, unless they are made of cotton. Making a bracha is pushing it.