Whats the process of getting approved for PBE?

It honestly just seems completely random to me. I've been playing this game for 4 years with only ever 1 chat restriction (When I was new to the game). So I'd say I have a pretty good record. But then I have a friend who's been playing the game for 3 months , got approved and shit talks almost every other game on live servers (Shes pretty freaking salty).

Like what honestly goes into picking people for PBE? I don't mean to complain but when your Toxic AF friend who's been playing for only 3 months and gets approved but you who've dedicated 4 years and rarely if ever shit talks doesn't. It just seems a bit odd to me.