As one of the most prestigious inter-club competitions in Europe, the Champions League never seems to run out of stories. Previously, no club was able to win the Champions League in two consecutive seasons or the defending champion always failed to defend the title in the following season, this myth has been broken by Real Madrid after successfully defending the Champions League title for three consecutive years.
The myth of a team that always wins the Champions League with 1 Croatian player in their team has continued for at least the last 10 years, Inter have the advantage in the Final this time because they have at least 1 Croatian player. This myth might be solved in this season's final, Manchester City went to the Final with great enthusiasm after beating Real Madrid, Manchester City is also equipped with a better squad compared to Inter. This final is very important for Manchester City and Guardiola, there is no reason to underestimate Inter quality even though Manchester City is superior to Inter.
There seems to be some Croatian love going around in the football topics, and I still do not understand why. It's a myth as you said and it's not a real thing and it's just a joke at this point. We all know City is far superior team and they will most likely win. If someone Inter ends up being the winner, which is a very low chance for that to happen, I am pretty sure that it is not going to be because they had a Croatian player on their team, that has nothing to do with the winner at all.
I personally hope that it's not going to be an important factor in the game and they will just lose but if they win that's not going to be the difference maker. So why would we care which team has one and which team doesn't have one at all.
That information is nothing but some interesting trivia, now if on each one of those championships the Croatian player had a lot to do with obtaining the win then the information would be worthy to look into it, but since that is not the case then is useless to think much about it, this is quite common on the world of sports, as people try to find some patterns that allow them to predict the winner they stumble on data like this, unfortunately while interesting this has zero effect on the game.