This is from January 2019, five months after BfA release.
While this thread from June 2019, ten months after BfA release, indicates BRF was doable, this quote from the 4th post adequately demonstrates that the bosses weren’t one shottable: “You can solo Mythic at that ilevel. There are mechanics to be aware and of”
There are no mechanics when you kill the boss with the first hit.
Do you want more or will those be sufficient?