Buddhism

That's kinda the benefit of Buddhism. It's (at heart) non-theistic. While it is a religion, the lack of deity being involved makes it rather portable. Almost all of it comes down to recognition of how living works, and applying tools to that to minimize suffering.

Yeah, there's spiritual aspects to it, but you don't need those to follow the rest, because it still provides the same tools, just without the spiritual goal.

The only real barrier to entry is accepting that the first two noble truths are indeed true. The first is easy because anyone looking into religion, spirituality, or similar ways of thinking tend to have an awareness that life as we experience it is unfulfilling, often laced with suffering. The second just takes a willingness to consider that it may be our way of thinking and living that contributes to the first truth.

Once one is willing to consider that as a possible truth, there's no barrier to trying the next two on and seeing if they're going to rise to the level of truth as people tend to think of it; in other words, do they work in practice?

The third is essentially agreeing to give the fourth a shot, if you're coming at it from the perspective of a modern western way of thinking. So, life is rough, and change is the only constant; maybe finding a path to letting go of the rejection of change via attachment and living in a more thoughtful way will help.

You hit the fourth, and it's pretty easy to try out. There's no threats of deity being mad, there's no bullshit, there's just a way of looking at the world and living by precepts as best you can.

Mind you, there's plenty of ways to go about that, depending on which "school" of Buddhism you subscribe to. And it can cuddle up with most other religions quite well. Not the key is that you don't need much in the way of faith at all. Just a willingness to consider a way of thinking and living, then try it.

That trying never ends, tbh. But I've found that the trying makes life better for myself and everyone around me, despite being a pretty bad Buddhist overall. I have too much attachment to my anger, if I'm being honest with myself. Makes navigating the path difficult.

I can say that I'm a better person than I used to be though. So I keep trying.