In three format of cricket, T20,ODI & TEST, comparatively Bangladesh team is good in ODI format, in ODI their rank is above Afghanistan & West Indies teams. But BAN team can't good performed from the World Cup 2023, they played worst i think, So i don’t want to judge them for this win against big team New Zealand, anything can happened in cricket. Yes, i have noticed that no batsman in Bangladesh team has to take runs consistently from World Cup 2023 except Mahmudullah. So, i think their main weakness of batting line, most of the ODI matches they can't play 50 overs, so they can't make a big score.
Among these three formats test is toughest, and then we have some good similarity in other two formats but still these all needed good talent quality and consistency which is possible with having good system into your domestic set up because if players are coming from grassroots then surely they can understand better technique and knowledge of the game which is also the best way for grooming of players in last three decades we have no improvement in Bangladesh domestic setup even now BPL is good and giving them good finances.
Now it's time for them to think about this all and create better environment which will help to increase quality and performance of players in all formats, otherwise having better ranking than teams like Afghanistan and West Indies is never good.
Bangladeshi players got talents but they lack consistency a lot. Every match they depend on a batter to score big innings to gather a good score. They don't perform like a team, their batting is very weak.
In the 2nd ODI Soumya played good but they couldn't defend it. Their bowling is average right now, but their batting is worse than Afghanistan's. No one in that team is consistent. Shanto looked a bit consistent earlier this year but he can't score runs here and there. Litton last year had the time of his life and now he gets out in soft dismissals like he used to. Tamim Iqbal doesn't play anymore, Shakib can't score much runs, and neither can Mushfiq and others. Towhid Hridoy looked like a good player with lots of potential but he has yet to show it. Tanzim Tamim looks like a good batter but he lacks discipline. Their batting is what letting them down each time. They couldn't chase a low run against Netherlands in the World Cup.
So I would agree with @mdzahed134, we shouldn't be saying Bangladesh has become good because that's only 1 match.