Your statement is false.

Jainism has no Gods whatsoever.

Mahayana Buddhists often don't believe in any gods, though the variety of practice is quite wide.

They consider Buddha was "just some guy", though a very wise one, and that there have been a million other Buddhas through history.

I consider my desire to reduce my footprint on the Earth - through a plant-based diet, by never having owned an internal combustion engine, and that sort of thing - some sort of spiritual practice.

And the reason is simple.

I'm not stupid enough to believe that personal choices made by me will have any effect on what's going to happen, which is that we will continue to consume at exponentially rising levels and devastate the biosphere.

This is a certainty. Humans are surprisingly foresightful for animals, but have nowhere near enough to act now to avoid a crisis decades down the line. Many of us are compassionate beings, but a lot of us are sociopaths and psychopaths, and Western society rewards them by allowing their to consume pathologically large amounts.

So practically speaking, it's pointless not to participate in the Rape of Gaia. But I choose to reduce my consumption as much as possible, simply for my soul - just so I can say, "I tried."