Your app and DB should be deployed together in the same datacenter to minimize latency between app and DB. Nothing should be hitting your DB besides your app and any etl tools if applicable. So latency to your DB shouldn’t be an issue.

If you need to add redundancy with a deployment in another region you should consider having separate environments between regions with totally separate data which allows you to better manage data protection/export regulations appropriately.

If that doesn’t work you’ll need a multi region database, a vendor with support for that such as aws rds would be the sanest method but you can always hack it yourself.

There’s other options but those require an architecture designed to be heavily distributed and that depends a lot on the nature of your application and you’d ideally hire an architect experienced in such deployments.