Shortening the catalog sync interval?

This is not really necessary.
1. the chance that a node goes down is low/rare
2. even if it did, there is a seconday node which has the catalog changes. the secondary will persist these changes to s3
3. If both primary and secondary go down (very very rare) and the catalog was on a EBS volume , It will be synced on next restart (assuming delete on termination of catalog vol is disabled)

The disadvantage of making it every 1 min is you are writing the entire Tx log to s3 every 1 min, and the Tx log can get large (i.e. about 1/2 the size of the catalog on disk). By making it every 1 min you are creating a lot of network and i/o load all the time for insurance against a very rare event (i.e. two nodes getting terminated including termination of their volumes) to ensure against a minimal loss (5 min).