Betta Fish: Is a 20 gallon tank overkill for one betta (and two snails)?

Am I an idiot for putting one betta in a 20 gallon?

I’ve had him about 6 months. Tank was fully cycled before he went in. He lives with two nerite snails, who are beloved and excellent at their jobs.

Water parameters are perfect, and yes, I use the real test kit, not strips.

I still get some brown algae, so every other week I do a light cleaning and gently vacuum the bottom. I do not go nuts cleaning because I already learned that lesson the hard way.

He uses the whole tank. He hangs near the top a lot, but he also swims all over, goes through the plant roots, checks everything out, and clearly knows it’s all his.

His tail is a little jagged because he insists on wedging himself through things like he’s indestructible.

He also turned into a picky little asshole after I gave him frozen shrimp. We had a full standoff where he refused to eat for about three days. Then I gave him Fluval Bug Bites and suddenly he remembered how food works and devoured them.

I’m honestly afraid to add any other fish because I do not feel like introducing parasites, ich, or any other nonsense into a tank that is otherwise doing great. He seems happy, and I don’t really want to screw that up just because I feel like a 20 gallon should have more in it.

So am I an idiot, or is one spoiled betta and his two very dedicated snail employees actually fine?

Before anyone says something. There IS a lid on the tank. It was folded in half in this pic because I was moving the pothos around.