The issue isn't immigration, it is massive amounts of illegal immigration. Some form of vetting is necessary to keep gang members, murderers, rapists, and extremist terrorists from entering the country. Nearly everyone in this country either is descended from immigrants or is a first generation immigrant themselves, but they just want a controlled legal process to occur.
Same with abortion. Trump's official position on abortion is that it isn't a federal issue, it is a state issue. This is much more nuanced than for and against. Conservatives have wide ranging beliefs on this issue. There are some that are 100% against it and some that believe it should be banned after X number of weeks. Many also believe that there should be exceptions for medical necessity, rape, and incest. There are complicated ethical, moral, and religious issues that surround these beliefs. At what point does a fetus become a human? No one really has a great answer to that question.
Another issue is gun control. If you believe strongly in the Second Amendment most Democrats are unpalatable on this issue alone. Kamala Harris has in the past stated that she supports a ban and confiscation of AR-15s, as you can imagine this went over poorly for a very significant portion of the electorate.
Bottom line however, I agree with many others here that the economy is the biggest thing that won people over to Trump. Even if it is completely out of Trump, Biden, or Harris's control, most people in this country felt like they were better off financially under the Trump administration and they voted accordingly.