Competing ethnicities with conflicting cultures under one roof has never worked well. In America, the ultimate crossroads of immigrants from around the world, the core values at a societal level to address this tension were to tolerate different beliefs and cultures and then use the education system as a tool to absorb the children of immigrants as full blooded Americans.

In recent years things are changing rather than turning various immigrant identity groups into Americans or British, we are seeing the various identities preserve their identities and begin to think in terms of competing identity groups for income, wealth, and political power. This is dangerous and always leads to violence.

It has nothing to do with MAGA ideology, since you find the same conflict all over the world where tribalism exists.

When these tribal conflicts include a religious difference, it can be even more violent. Many European countries are going to go through their own version of "civil war". I believe an early step of all those countries will be to shut down their borders and figure out to how to end the separatism and build national unity instead of group identity. But these efforts may well take a generation or more.