AWS RDS. Long time RDS responses (US region) with EC2 Singapore. How to decide?

Question

Amazon Web Services

what a problem. There is MySQL RDS. In the US (Oregon) region. All EC2 are in it. Now there is a need for EC2 in the Asia region. Singapore. Only time to reach from Singapore to US RDS - 5-7 sec. (Read replica is not suitable, you need to read and write)

Answer 1

It seems that you have problems with the architecture. These are remote regions and, of course, there may be problems (although 5-7 seconds is, of course, overkill. You measured what exactly this time is spent on)
And why do you need EC2 in Asia? In most cases, the regional presence is decided through the CDN, and the server for processing is placed closer to the database.
Tell us in more detail what solutions you have and why. Ideally with a network architecture (a sketch from Lucidcharts or draw.io is more than adequate)