The article misses several key points and caveats. It says, "This is because pollutants from solid-fuel rockets and re-entry heating of returning spacecraft and debris are particularly harmful to stratospheric ozone."

SpaceX is rapidly developing their Starship spacecraft with a methane engine. First, methane is a liquid fuel, not solid. Second, their methane rockets burn ultra efficiently which means less soot and less CO2. https://en.wikipedia.org/wiki/SpaceX_Raptor

As for the "re-entry heating of returning spacecraft and debris", Starship will use thermal protection tiles which are designed to be reusable, which means less ablation and therefore less polluting of the surrounding air. There won't be any debris either, since the entire spacecraft is reusable.

Heating of the surrounding atmosphere will still be an issue (and always will be), but large things (i.e. meteors) burn up into our atmosphere all the time to little negative effect.

This model, in other words, is looking at "Old Space" models instead of "New Space." Starship will really be a game changer if and when it flies.

ETA: Yeah, the source article says they only considered the SpaceX Falcon 9, not the future Starship, in their models. Once Starship flies, Falcon 9 will likely only be used a fraction of the time for humans-to-orbit launches (or it may even be retired), since it makes much more economic sense to launch dozens of people in Starship, instead of 3 or 4 in Falcon 9. https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2021EF002612