There is no reason to debate people like Destiny or Vaush. They ask for a study for common trends or commonly understood facts about a topic. You basically have to bring a binder full of statistics and URL links for everything you are talking about. The other issue they always frame the debate based on leftist premises. Miyo didn't want to explicitly advocate for White interests and frame himself like a civic nationalist. If your a white nationalist the immigration question is easy.

1) It reduces social trust and civic participation.

2) it increases crime rate if the ethnic groups immigrating have a higher rate of crime than the native population.

3) It creates fragmentation in politics and communities. People complain people are on the internet all of the time and social media but part of this reason is that immigration and desegregation destroyed White communities. People are not going to go outside if there is nobody like them to hang out with or if it threatens their life if they live by hostile ethnic groups like Blacks.

4) It is often used as a union buster because worker scabs will work for lower wages and lack of unity required to organize a labor union or worker strike.

5) White people have enough intelligent people to fill the high IQ jobs. We don't need Asians or Indians in tech jobs.

6) Bringing in immigrants threatens national security because they steal secrets in the government or steal intellectual property if they work for large tech corporations.

7) They have different value systems, social etiquette and different preferences that fracture communities. The more similar people are in a community the more they often get along and also work efficiently.

8) White people are demonized by the media and non-Whites believe in these narratives. This will cause more racial discrimination against Whites that will only amplify when they become a minority in their homelands. There is no reason to believe the opposite will happen because they benefit from claiming White people are racist. Even if White people become a powerless minority they will never have a change of heart. Critical race theory provides the intellectual justification for non whites to always claim White people are racist forever because it denies differences in racial groups. Since White people on average will be better than other groups at some things they can never not be racist. The term racist is always used only against White people anyway.

9) Non-whites don't assimilate to White culture or will ever be considered White. This is because of the genetic differences between groups, cultural differences, politics and historical grievances. Also non whites get preferential treatment by many large multinational corporations and the government. It is not their interest to have equality and they only speak of equality because it favors their own ethnic interests. They aren't genuine Americans or good faith liberals.

10) It is not in the interest of White people to have more people living in their society that are non-White. Every sovereign ethnic group has the right to their own borders and homelands. The UN protects indigenous rights of all ethnic groups and the fact they don't extend this to Whites shows grave hypocrisy by the UN. Even if Whites were a inferior race that would benefit from high IQ immigration they still deserve human rights and the right to control their borders.

11) There is no point in history where mass immigration was every positive for the dominant ethnic group. Even when there is assimilation the divergent interests often still exist under the surface well past people remembering that those groups were different and had their ancient feuds.