Betta Fish: Does our boy Ali Betta look healthy?

Hi dear sub members,

Here is the lil friend we've had since late August. He loves swimming through the tree hut we made him, which looks like a cave, so we call him Ali Betta. He's also a really good plant surfer, as you can see in pic 5, and recently started to show us he was a wizard and could fly a broom, as seen in pic 4, so we also started calling him Ali Potter.

I was wondering if he seemed happy and healthy enough and what people from this sub thought. Does his colouring look okay? Some days he looks a bit white-ish but it might just be the lighting.
He lives in a 20L (5G?) tank, with a rabbit snail and 5 Endlers guppies. He lived with blue dream shrimp but only for a very short while as he started eating them. We know the substrate layer is too thick but it's too late to remove it now.