I guess it's not possible to design a tea bag that's not made out of plastic but that can also survive the boiling hot temperatures?
Plastic tea bags are rare in Germany, although they are getting more popular. Tea bags are usually paper, apparently made from this plant: https://en.m.wikipedia.org/wiki/Abac%C3%A1
Also TIL: Manila hemp.. Manila envelope.. jupp, they were also made from that fiber up until some time ago.