that’s not what the Catholic Church means by ‘know’. What the Catholic Church teaches is those who through no fault of their own do not know that the Catholic Church is the one true church founded by Jesus Christ can still be saved.
But if you KNOW in your mind and heart that the Catholic Church is the one true church and you still choose to walk away, then you are at risk of losing salvation.
So ‘knowing of’ the Catholic Church is not the same as ‘knowing’ the Catholic Church.
And all who are in heaven are Catholics regardless of what faith practice they held on earth. There is only one body of Christ, one Church.
This is not a boast nor is it arrogance it is just logic based on what the Church is by definition.