Buddhists teach negation of all earthly things including relations with others; their Nirvana is to merge with the All and thereby cease to exist as an individual.
American settlers picked up the idea that First Nations peoples looked forward to a “Happy Hunting Ground” – no idea whether that is remotely accurate, but the nominally Christian settlers “heard” the First Nations peoples through a filter o their own expectations.
Judaism in Jesus’ day held two different views, either that at bodily death the game was over, or at bodily death the spirit continued to exist. After Christianity arose, the “game over at death” camp seems to have dominated – corrections greatly appreciated.
Islam has its own idea of Heaven – a place where forbidden earthly pleasures are freely available.
Christians view Heaven as an eternity spent in the presence of a love and peace that pass all understanding.
This has been trivialized into harps and hymn sings, which are sufficiently boring to earn the sobriquet “pie in the sky bye and bye” – you figure out which one a GOD would intend.
Atheists profess that anything happening after the gray matter dies is a contradiction in terms (again, corrections gladly sought.)
“Same heaven” therefor assumes that one vision of heaven exists, and that Christians recognize it – – – making all others strangers there?