I think that it’s important to think not only outside yourself, but beyond your generation as well. Each generation should have the opportunity to do better than the one before, but while historically that’s been a possibility for ORMs it hasn’t been as easy for URMs. I think that’s why colleges may give the apps of URMs a closer look.
I think colleges take individual student circumstances into account, so if you come from a disadvantaged background they’ll consider that. I don’t believe you’ll be competing with URMs though. I think URMs compete with other URMs. But not all URMs are low income, so it makes sense that not all URMs who are accepted would be either.
However, if colleges ignored the economic backgrounds for URMs, it would only be fair for them to ignore the economic backgrounds of ORMs. Do you really want them to ignore the fact that some high schools offer much more than your “slightly below average opportunities”? I don’t believe you’ll be competing against URMs at all. I think you’ll be in different buckets, but even if you were it’s more likely that you’d be compared to students with similar backgrounds and opportunities. In short, if you don’t get into an Ivy or other highly ranked university it won’t be because some less qualified URM got in instead.