One problem with DEI is that many ethnicities get thrown under the white or white-adjacent umbrella and aren't given the same opportunities simply because the popular view of history doesn't seem them as historically oppressed when in fact they were. For instance, Armenians are a historically oppressed group, even genocided, yet they are not afforded any DEI perks in their career paths. Palestinians are also not included in DEI because it isn't politically expedient to side with them, even though they have lost their homeland and are generally treated like dogs. Many, many such groups exist but because they don't come up during AP US History, they have no mindshare.
Another is that DEI seems to simultaneously accept that race is a social construct while also using race as a key criterion for purposes of inclusion, which is absurd. For example, a Black Swede, growing up in Sweden her whole life, would be considered a candidate that improves diversity in the workplace. However, I'm not aware of Swedes being an oppressed people. In fact, growing up in Sweden your life is probably better than in America. The judgment is made purely on skin color and lineage.
Lastly, I also want to say that I know this is an ugly situation, because high paying jobs are often about connections, which have a strong correlation with ethnic background in the United States. In that view, it makes sense to have something like DEI shine a light on power structures within the workplace and make them more fair. So despite the above, I support DEI if it helps underprivileged people. After all racism still exists, and it's virulent. Many people harbor racist views and will lie through their teeth in order not to be canceled.
I just hope eventually racism is extinguished so we could move forward to a purely merit-based system.