1.) I cannot meaningfully apologize for slavery. I didn't enslave people or own slaves, nor did American slavery happen within 8 decades of my birth. Further, 3 of my 4 grandparents were immigrants or the child of immigrants who came to the US after slavery had been abolished, and my 4th grandparent's parents and ancestors were in the Midwest. While I've not searched demographic data, probably a majority of American "whites" could accurately say much the same of their ancestors.
2.) As noted above, no matter how far back one goes in my ancestry, none of my ancestry benefited from American slavery - through ownership or living in slave states. Further - and more to the point - slavery ended in 1865, 150 years ago. As vast numbers of immigrants have demonstrated, with hard work and education, the children and grandchildren of destitute, hated, immigrants were able to become prosperous, and sometimes wealthy. Many blacks denounced as "race traitors" and "Uncle Toms" have demonstrated the same. IOW, as horrible as the legacy of slavery has been, the effects of that were pretty much overcome by those who wanted to within 30-60 years. The same is true, BTW, of Jim Crow and "separate but equal", whose death began in the late 1940s or early 1950s.
Like a majority of "white" Americans, I have nothing to apologize for, and like almost all "white" Americans, I cannot meaningfully apologize for slavery or Jim Crow.