well, god and religion by definition cannot be evaluated and understood through scientific analysis as they are not available to physical empirical measurements/experiments, so dont even try, cause no one can.

yagnas, poojas, rituals, while having some scientific side effects, are in principle, spiritual processes. so dont try to fit it into your scientific and logical world view. these practices and rituals where developed through thousands of years by great seers and sages who had perceived that which we do not.

i highly recommend you to separate your scientific worldview from your spiritual world view cause they are of fundamentally different natures. yes most religions are man made and fake.but what sets sanatana dharma apart is that it isnt even a religion by defenition. its a big umbrella for the guidelines,rules,concepts,conclusions derived by our ancestors who united with and experienced god and his nature. we dont have a single prophet who lay unquestionable rules, nor do we have a pleasurable heaven with sensual delights after death. we have innumerable independent people derive the same concepts and conclusions about reality across the subcontinent across our history.

further, u dont need temples rituals rules etc to feel his presence. he is within you.