You can have a high case load in vaccinated countries and still have vaccines that reduce transmissions. Those two ideas don’t conflict.
It just means the vaccines we have don’t reduce transmission by 100% and you have a disease that is highly infectious. Just because a medical intervention doesn’t work 100% of the time doesn’t mean it’s 0% effective. Most interventions (vaccines, drugs, procedures, surgeries) don’t work at 100.0%.
From the data I’ve seen it appears the mRNA vaccines have some effect in reducing transmission while the other vaccines don’t. It is correct to say that the efficacy against transmission has dropped significantly, but that doesn’t mean it’s 0%.