Pertinent quote from the results section of the publication:
Most people who come from a socio-economically less favorable background do not commit more crime than people who come from a more favorable background, and it also happens that people from a more favorable background do commit crime. This means that even if there is a connection between socio-economic background and involvement in crime, that connection is weak. It is not possible to appreciably predict who will commit crimes based on knowledge of people's socio-economic background.
https://bra.se/publikationer/arkiv/publikationer/2023-03-01-socioekonomisk-bakgrund-och-brott.html
The bigger factor is fatherless homes. The black community was far more functional before LBJ and no fault divorce made welfare queen a feasible career option for black women. The real question is how the white community stayed somewhat functional when feminism started destroying their families. Some of it is surely IQ, but again the blacks weren't always like this, at least to the extent they are now.