Buddhism without practice is just blather. The same goes for any religion or philosophy.
Buddhism is a religion without a creation story or creator god. There are non-human beings called devas, but they are mortal and die. This word is translated as "god" but devas are not gods in the Western sense of the word. Buddhism talks about rebirth and its causes so there is an "afterlife" teaching. Rebirth makes Buddhism a religion.
There is no part of Buddhism that must be taken on blind faith. If one doesn't understand a concept one is free to put it aside and work on other aspects. One can revisit difficult concepts again and again over the space of years. Since one is not obligated to profess a faith, Buddhism is a moral philosophy.
For one to study and practice seriously one does have to have confidence that the effort is worth while. One has to have confidence that the teachings will lead to happiness. As one puts the teachings into practice, the confidence grows and deepens. But for atheists, there is a whole pile of woo to figure out first. This creates what Buddha called skeptical doubt. The way to overcome it is through analysis and practical experience leading to realization. Skeptical doubt is not considered bad or condemned. It is something that is accepted and faced head on. The teachings say that it isn't completely overcome until just prior to enlightenment; that time when knowing becomes realization.
One knows how to ride a bicycle by reading instructions. One can have doubt about the accuracy of the instructions so one has to test the instructions by actual physical effort, practice, experience. Then one realizes how to ride a bike.