You know, like I'm aware how scared you are that PK Luffy will 1v1 Sakazuki since that already guarantees that Akainu>Previous oponnents, but even if ( and the chance is small) you're right, Sabo himself will be a High Top Tier and one of the strongest by the end of this series

And yes, Sabo will prove himself to be a high top tier after he beats the strongest mid top tier, Akainu