I don't have a TCL Roku TV, but am going to need the same type of setup. Do you possibly have a link for the converter box that you had to buy? Thanks
Just find one that works for you here.
https://www.amazon.com/s?k=optical+output+splitter&page=3&qid=1679798933&ref=sr_pg_3
This is specifically the one I bought and it works well. I have both earphones and a sound bar hooked up to it.
https://www.amazon.com/gp/product/B07C6B5TTK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1