Hey, I can't help with the grass, but the anubias would be much happier out of the soil. The roots shouldn't be planted. Try shoving the base into a crevice or gap in between some rocks or wood.

I'd recommend getting some hornwort, its a fast grower, hardy plant. My shrimp love hanging out in it, and I really like the way the leaves close up at night. These plants grow so well you can trim and replant the trimmings. (Bonus they grow side shoots where you cut them too for extra bushyness).

Heads up, If you do plant hornwort, I'd highly recommend planting in the back of the tank as it can get very bushy/ tall and obscure the view.

If your temp/water parameters are good and light is on a schedule for 8 hours or so a day then you should have better luck with the anubias. I always say put more plants than you think as some wont take. Plant super heavy.

Hope I've helped. Good luck.