This young woman put together a documentary on Japan’s relationship to Christianity, how its perceived, what Japanese people do believe and how Christians are received in the Land of the Rising Sun.
When I lived there, Christianity was perceived as a foreign religion and as the video states only 1% of the population believes in it. Still because its a densely populated country, I did find churches near me.
I attended Buddhist and Shinto festivals, but as the documentary shows people tended to do them because they were traditions not because they actually believed them or knew their origins. At temples people would post their prayer petitions and people do donate to support their temples, in fact there’s great social pressure to tithe.