I don’t have references for this, but my understanding is that you have more to worry about space debris that is higher/faster than lower/slower. The atmospheric drag is such that any out of control craft at [some threshold] or under will deorbit themselves fairly quickly, and the debris will burn up entirely. I believe that threshold is around 450-500km, but it’s also probably not a literal height, more of a gradient of risk. Higher/faster, they will be up there for longer (years? decades?) and it’s harder to predict where any broken pieces will go over time.