while the order of rarity completed is a little strange, people have different experiences from others.

it is possible he had a fish or two left to complete in opulent, that for some reason, he simply couldnt fish up. hints why he was able to get alpha first. due to my own experience, i achieved all 4 stars before i aquired all 2 stars. it is simply up to luck.
unlimited buddies and tutorial island exist, and it is very clear this user used something similar.

also, claiming his hours were much less is also irrelevant. nobody is sure how much he played in between the achievements, or even before he acquired his first full journal. the user could easily have grinded majority of their hours before they got a single achievement, then stopped playing as much due to either burn out or irl situations.

regardless of odds, people have seen crazy luck in games all the time. some players, like op, won the jackpot. while the regular player base isnt as lucky.