What is the ruling on eating meat available in Australia about which a Muslim is not certain if it was slaughtered according to Islamic law, and does it fall under the ruling of the food of the People of the Book? And what is your advice regarding going to a distant mosque to perform the daily prayers?

The slaughtered animals of theশীল People of the Book are permissible unless there is an indication that they were not slaughtered according to Islamic law. If the reality is that you find no one to pray in congregation with you except disbelievers, then you have an excuse for not performing congregational prayers. If it is possible for you to pray in congregation outside the mosque, then strive to do so.