that's definitely rigged. the chance to get that rarity is 1 in 10 trillion. you'd have a 200x higher chance of winning the powerball than you would have a chance of winning that.
edit: i just read the chapter fully and i have to say that for a 1 in 10 trillion chance of getting that rarity item, the effects are subpar. for something that requires an almost god-like level of luck to get, you'd imagine he'd become a god after or something just outrageous. nope, he can just sync with another person. While that's a good ability and the character is strong, the rarity doesn't equal the reward.
i also feel the need to mention that just because there's a chance to get something and the rarity is high enough, "possible" doesn’t mean practically achievable. let's say for example, an item has a rarity of 1 in 10^23. (1 in 100 sextillion) while it's theoretically possible to win it, realistically speaking, there's a 0% chance that you're gonna get it. you’d need more than the entire age of the universe to get it even ONCE.
to put it into even more perspective: even if you had one chance per second for the entire age of the universe, you’d still have less than a 0.000001% chance of winning even one time. so, impossible is putting it lightly. while 1 in 10 trillion is much less outlandish than 1 in 10^23, it's still pretty far into the realm of impossibility.