Some matter of facts, regardless what jiburiru or other managers would say.

1) the longer you stayed away from the game the higher the chance to get lucky in those rng events.

2) the lower your total power/ranking in your server the higher the chance to get lucky in those events.

3) the earlier you roll in them during the day, the higher the chances.

4) if somebody else won the top prize just a moment before you, depending on the event, or you can get again the top reward very closely (within the following 100 rolls) or for the rest of the day none else will get it. There's no half measures.

So if you don't play since, lets say, 1 year and you came back lately, you are not even remotely close to your server top10 and top128 in your spacetime bracket and you roll in early morning, not long after the end of the maintenance and none else got the top prize before you in the same day, then you are more or less guaranteed to get it.