Lol I have a yellow bellied (yellow eared) and a red eared. The yellow belly avoids eating most plants and sticks with the controlling the guppy colony population. I, currently, don't have my turtle tub planted, just floaters, but at one point I did have a ball using hydroponic containers and marginal plants had success with rushes and reeds. My red eared eats everything except hornwort and water lettuce. I fully agree this will be a never ending process, on top of eating vegetation turtles LOVE to dig up anything you plant in the substrate. If you're going with java ferns you're going to want to tie them to something that's not easily accessible to the turtle, but expect that they will try to tear it out. Oscars and turtles, in my experience, have the same rate of plant acceptance lol. Good luck and welcome!!
*Edit- your turtle, most likely, won't eat the moss but will tear it up. This will most likely have it spreading to unexpected areas of your tank. If you don't mind that then just make sure to remove any from the filter when you water change.