I am sorry I don't have the precise statement about relative rates of gun deaths and mass shootings in the US vs the rest of the OECD. Here's a data point to ponder, firearms are now the leading cause of death for children and adolescents in the US: https://www.nejm.org/doi/full/10.1056/NEJMc2201761
I wa surprised by this, because Mexico is in the OECD. According to https://www.frontiersin.org/journals/public-health/articles/..., the firearm-related death rate (including suicides and accidents) in 2022 in Mexico for children and adolescents (age 1-19) is 4.9/100k, compared to 5.9/100k in the US. But the overall homicide rate is 6.5/100k for Mexico vs 4.7/100k in the US. So this is consistent with Mexico being a more violent society than the US, but using somewhat fewer guns in the process (and the numbers are still pretty similar). There's also questions about how reliable the Mexican firearm homicide data is - a lot of these are presumably happening in cartel-controlled areas where Mexican government state capacity is limited, including the capacity to properly gather statistics.
As is "doesn't seem to have a problem."