Free-roaming animals reintroduced in Romania’s Țarcu mountains are stimulating plant growth and securing carbon stored in the soil while grazing

I’m confused here because didn’t they think cows were causing methane problems (separate issue?) and why don’t cows help take CO2 out of air compared to bison? So could just having a lot more big animals (other animals mentioned in article I think?) help take CO2 out of the air, or is this kind of like the trillion trees project which was plants now being applied to animals… will it work? No? Thoughts on the situation?