I recognize that racism is a major issue in tech, it's structurally dominated by white men - and while that is slowly changing people (especially larger companies where significant racial biases in the employee database are much stronger indications of employment bias than in smaller companies[1]), but no even in that environment you can't say we will hire/fire with the specific intent of getting a specific racial mix. Whether that mix be the good old white supremacist one, or an intentionally equal one. Firing would seem to not be something where you could reasonably do any form of intentional equalisation w/o it being pretty overt, and illegal, racial bias.

The way to correct the racial balance in a company (again one large enough for statistics of employee vs national or regional racial make up to be relevant), is to first address your hiring practices and college or university outreach. Because the reality is people are still more likely to get to the interview stage via nepotism: one of your employees gets a hiring or intern suggestion from their old PI, your employees go back to the school they went to for career fair/outreach programs. Historically for example tech companies did very little outreach at any of the HBCUs or community colleges, which for historical (often racist) reasons are where the major you get a much more representative of society group of people. Aside from anything else that not only means talented people from those schools are less likely to get the experience from, say, interning, but also it means you're missing out on the talent that didn't get lucky enough in where they were born or who their parents were.

What I'm trying to say is that I do not believe you can in any way fire your way to a less racist company, but you can do a lot to fix it by making sure your hiring process isn't automatically removing swathes of the population due not to explicit racism but simply habit and the path of least resistance. You shouldn't be in a position where you are saying yes or no about a person simply because of their race, and saying yes or no simply because of the school they went to is at a gross statistical level fairly equivalent to doing just that.

[1] Because statistics