Its true im many places. First generation hard working. Second generation lives in the inprint of the first generation. Third generation has no connection to the original homeland and tries to find connection or it turns to antisocial behaviour.
Worth specifying that this also applies to the "good" immigrants such as the Poles, not just the much vilified Muslims. The kids of Polish immigrants really struggle. And if you go a generation back, the Vietnamese boat refugees had similar issues: their kids really had issues, there were Vietnamese criminal gangs in Oslo in the 90s. The ex-Yugoslav organized crime groups were maybe more notable in that they were often first generation, but they're mostly a memory too by now.
Then there's the "hapas", children of Asian women who immigrated by marrying native men. Scandinavia hasn't seen much trouble with them - yet. But I think there's some danger here, online I've seen some worrying communities.
I think identity rootlessness is an underestimated factor in immigration woes. Youth of all kinds can often be exploited into adopting a destructive self-identity, but some groups are more vulnerable. One notorious Swedish gang actively recruits from the foster care system.
I think less people expected those to cause generational trouble and so a common pro-migration argument 1-2 decades ago was that these people from mena regions would assimilate. After all the people from (in our case italy) mostly already did.
It's wild to see how this flipped completely around in such a short time and now some markers of integration seem to go backwards and at the same time some consider it biggoted to demand/expect assimilation.
You only have to look at Trump; third generation immigrant.
His grandfather made his fortune by operating a restaurant and a brothel for miners in Whitehorse during the Gold Rush years, his father compounded that with an actual real estate 'empire' and the grandson 'earnt' money via dodgy wealth transfer schemes and sank much of it into get rich quick scams and branding deals based on fraudulent representation and money laundering, now leading the country in historic levels of open corruption.
Ok, this is very different from the situation in Sweden.
Many were analphabets and live completely segregated from mainstream society with little hope(or wish) to integrate with Swedish society.
I agree with your analysis of the Trump family who have been detrimental for US society.
Near as I can tell, Trump III is also an analphabet, living completely segregated from mainstream society with little hope(or wish) to integrate with Swedish society (or US for that matter).
Questions for Sweden might be "How did the US integrate all the illiterate Irish?" (and should they do the same), "How did Australia integrate many non English speaking / writing Vietnamese 'boat people'?", etc.
Unless Sweden in majority is prepared to broom out all that they have accepted in, then this how it is, a mix of cultures having to find common directions and minimise friction over the next generation and a half.
It is not like that where I live.
The first generation of immigrants have trouble, natural enough. But are very keen that their children do better.
As for racism: Most racism here is systemic, from the state. There is casual ignorant racism, of course, but little hate.
What a mess has been made of your country. You should work to fix it.
It took us a lot of work to get here, and we have a long way to go. But I cannot imagine living in a society such as you describe.