There was no RNG involved in getting the beta key other than the Day 1 drops. If you watched one of the approved streamers during Day 2 for 4 hours, you got the key.
Apparently there were some issues for some people so read over this thread and see if it solves your issue
but for the most part, people having problems just hadn’t linked their Bnet and Twitch accounts and thus couldn’t install even if they got the drop.
If it still doesn’t work, some OWL teams are doing give aways and there will be keys given out during OWL opening week end.
i was pretty much expecting get into the beta through an initial e-mail
this happened for remarkably few people, and the account’s play time, age, etc, had nothing to do with it. It was just a lotto.