Are Heaven(s) and Hell(s) literal? How do we know that they're real & actually exist?

I'm very close to becoming a Buddhist, of some strand of Mahayana, but I am having some difficulties with the concept of Heaven(s) and Hell(s). I already know that some such as [Hakuin Ekaku](https://buddhism.stackexchange.com/a/3503/25543) of the Rinzai Japanese Zen Buddhism viewed Heaven(s) and Hell(s) as a state of mind. I've heard the same about the Madhyamaka school of Buddhist philosophy (e.g. Nagarjuna's views). This is a view that I can accept, but I don't think its common in Mahayana sects. Nevertheless, from what I've seen though I wasn't able to confirm, it seems that for many, if not most sects and schools of Mahayana Buddhism view Heaven(s) and Hell(s) as real and literal places. Therefore, my question is whether they're actually literal about how do we know that they're real if we are genuinely unable to verify that they exist, either logically or empirically via experimentation. Also, if you know of any Mahayana sects which view Heaven(s) and Hell(s) as psychological states of mind, do let me know please.