There is a massive tradition, spanning thousands of years, of people trying to wrestle with morality and the good life with or without a God involved. We broadly call it Ethics in Philosophy, and you can spend an entire lifetime exploring and glimpsing what is at the core of this "being a good human" with or without a God involved.

On "good comes from religion"... you can start with the western classics (or eastern classics, but I do not know them) https://plato.stanford.edu/entries/plato-ethics/ https://plato.stanford.edu/entries/aristotle-ethics/

Then maybe take a course or two on Ethics https://ocw.mit.edu/courses/linguistics-and-philosophy/24-23...

Then explore from there.

You can spend a few weekends or a lifetime on this if you'd like, and either way it will be worth the time.

As a 100% atheist, I disagree strongly with every single one of your statements.

To elaborate,

> Most anthiests seem to be nihilists

Not true

> they're already (claiming to be) doing that

No, they're not

> the logical conundrum of "I don't need a God or theology to live a good life"

There's no conundrum or contradiction here, plenty of us live good lives

> our constructed definition of "good" comes from religion

Sounds like a made-up fact. I don't need an omnipotent third party to validate that taking another person's life, or stealing from them, etc. is not right. Empathy and the idea of "do unto others" are quite easily understandable and relatable outside of the context of religion.

> I just always find it strange the way that “100% athiests” seem to ignore the logical conundrum of “I don’t need a God or theology to live a good life” when our constructed definition of “good” comes from religion.

“The people that came up with <useful idea> also believed <useless idea>” does not imply that “To benefit from or further refine <useful idea>, one must also accept <useless idea>”.

(I don’t see religion as useless, but there is no reason people who do would have any problem adapting and refining moral ideas first developed in a religious context, any more than religious people do for ideas developed in different religious contexts than their own.)

There are centuries (millennia?) of philosophical thought on ethics and morality that is disconnected from religion.

https://en.wikipedia.org/wiki/Ethics

You can define good as you want, no need to have a religion define it for you.

I believe the main characteristic that takes apart atheist from other belief systems is that ultimately without a god that objectively defines what is good, one must define by himself what is good. This one one side is liberating because there is no more pressure between what one thinks is right and what the religion tell them, but at the same time extremely difficult because one exposes themself to all their psychological weaknesses (and to whom can manipulate them).

Nietzsche addresses this best in Beyond Good and Evil, we can cast if the constructed definitions from religion of “Good” and “Evil” and instead subjectively form our own morality based on what we find good or bad. But the constructed version of morality today comes more from culture and media than religion.

That just seems completely incorrect. Most people in my life are atheists and not nihilists, and the few exceptions are all religious rather than nihilists.

"Our constructed definition of 'good' comes from religion."

I am wondering what makes you think that?

Says who? Most atheists I've met are humanists.