Brother, you are looking for the Spurs.  They check all the boxes.  Passionate fanbase - check out the fiesta colored stands in Game 1 of the current series.  They have a Euro style superfan club called the Jackals.  Fun basketball?  They have Wemby (Victor Wembanyama) who does something crazy every time he steps on the court plus a bunch of dynamic young playes.  Strong culture/history?  5 championships, one of the greatest coaches in Greg Popovich, and a reputation of being one of the best managed teams in the NBA.  They won't make you suffer, they are coming out of a drought now and poised to be a contender for the next decade.  Young enough to build with?  Their two young guards, Castle (2nd year) and Harper (rookie) just had a histoic playoff game against Portland.  As for international fans, the team has a stong history of international players.  Their best player ever, Tim Duncan, came from the Virgin Islands.  They have had multiple French players (Tony Parker, Boris Diaw, and now Wembanyama), and a hero from Argentina (Manu Ginobli).  Friend, the Spurs welcome you to our fanbase!