It's genuinely shocking how good he actually is. How can a player who has never scored more than 8 goals in a season, in 2 really weak leagues, suddenly turn up and look like he is going to score or assist every time he gets the ball? It seems these La Masia lads will always play their best football at the club that built them.
I don't know about his spell at Germany, but his stats at Dinamo Zagreb (Croatia) aren't that bad in spite of him scoring only 8 league goals per season.
When you dig slightly deeper into his numbers, they look better.
Here is why:
1. Croatian 1st league lately has an average of goals scored per game around 2,50-2,60, closer to Seria A football.
While for example, England and Germany have around 3,20 goals scored per match.
So, in some countries, matches are closer to 4:0 and 3:3 all the time while in some other countries, matches are closer to 1:0 and 2:1 all the time.
2. during his time at Dinamo, he played far from the goal, he was a kid in a foreign country (aged 19-20-21) and his 2 and a half seasons here, these are his numbers compared to domestic Croatian (mostly NT) players:
2017-2020:
52 matches, 19 goals = 0,37 goals per match = NT LW Orsic
60 matches, 19 goals = 0,32 goals per match = Olmo
50 matches, 16 goals = 0,32 goals per match = NT CF Petkovic
56 matches, 7 goals = 0,13 goals per match = Cm Ademi
31 matches, 3 goals = 0,10 goals per match = NT Cm Lovro Majer (plays for Wolfsburg currently, scored 2 goals and hit the post twice against Bayern last weekend)
43 matches, 4 goals = 0,09 goals per match = winger Hajrovic
In short:
1. he just came to the club
2. to the totally different culture, different type of football, different teammates than at Barcelona, didn't know the language
3. yet, from the day 1 he was the 2nd best scorer of the team, even though he played on deeper positions than regular forwards
4. and he scored the same amount of goals, as let's say NT CF Bruno Petkovic, who was also taking penalty kicks
5. the only player who was scoring more than him was a winger Orsic who was at a peak of his career back then (scored a hattrick vs Mourinho's Tottenham, for example)
So, imo, being the team's 2nd best scorer in a foreign country as a teen kid is really not a bad achievement.
And scored some crazy bangers, like this volley against Manchester City in a Champions league:
So, he was always an awesome player.
He was just kinda "under the radar".
Probably other teams hestitated to buy him because Barcelona has rejected him in the first place (when he moved to Dinamo), so other clubs probably thought: "there must be something wrong with him if Barca has let him go that easily".