Seneca taught us that contented poverty is an honourable estate.

Sounds like propaganda from horrible dystopian society.

Although there was a study done on lottery winners to see if they were happier after 6 months. They were not

So stop all the commercials telling us how much better things can be

Freedom from what?

I think there's an important distinction to make with this: contentment vs complacency. They're similar, but distinct. Contentment resonates more with the gratefulness aspect of your statement, whereas "wanting nothing" leans more toward complacency. Contentment is more oriented with a sense of joy or peace, whereas complacency is apathetic and numb. Only one of those sounds like freedom to me.

In addition, I would argue that it's impossible for a human to truly "want nothing" (sorry Buddhist friends). Even the most enlightened soul would desire to see peace throughout the world. In fact, if you truly wanted nothing, I don't think gratefulness would even be possible--what is there to be grateful for if you didn't want any of it in the first place?

Related reading: the Oatmeal on Happiness

he who knows when enough is enough will always have enough

I mean. sounds like buddhism.

As someone who is driven to create, this is just not true for me. I am constantly wanting this or that in order to create something magical. Just accepting what is, does not lead to creation. Being creative is freedom for me.

I certainly haven't figure out how to be happy without being grateful. And I've noticed comparison seems to serve little purpose other than to undermine gratitude.

To quote the decimal system:

I expect nothing, and I'm still let down.

Might be happiness for some, but it's certainly not freedom, in any normal sense of the word.

Buddhism?

I like ducks 🦆