The tank looks good
I would add some Water Sprite (Ceratopteris thalilctroides/ cornuta). It's a floating plant that has branches and the Bettas can sleep among the branches and be near the surface.
I would also keep an eye on the areas behind the rocks. Gunk can build up there and cause water quality problems.
Keep an eye on the Betta in the top left corner (up the front). It looks stressed and might be getting bullied.
Apart from that, good job