Lightsail instance "relocate"

There isn't a direct way to relocate your Lightsail instance to another physical host while keeping it as the same instance. As you correctly understood, the standard process to effectively "move" a Lightsail instance involves:

1. Creating a snapshot of your current instance
2. Using that snapshot to create a new instance with the same or different specifications
3. If you're using a static IP, detaching it from the old instance and attaching it to the new one to maintain the same IP address
4. Updating any necessary DNS settings if you're using a domain name
5. Testing the new instance to ensure everything works correctly
6. Stopping or deleting the old instance once you've confirmed the new one is functioning properly

This process allows you to maintain your data and configurations while potentially resolving performance issues that might be related to the underlying host. The new instance will be created on different physical hardware, which could resolve the slowness you're experiencing.

Keep in mind that when creating the new instance from a snapshot, you'll have the opportunity to select different options if desired, such as a different Availability Zone within the same region or even upgrading to a larger plan if you think you might need more resources.
Sources
Lightsail Instance Upgrade | AWS re:Post
Upgrading the AWS Lightsail instance | AWS re:Post
Create Lightsail instances from snapshots - Amazon Lightsail

If your Lightsail instance has become unexpectedly slow while showing low resource usage, it may be a symptom of a problem with the underlying physical host. Relocating your instance within the same region can potentially resolve this.

Here, Relocation Procedure in Lightsail:

1. Create a snapshot of your current Lightsail instance through the Lightsail console.
2. Launch a new instance from that snapshot in the same region, selecting your preferred availability zone.
3. Test the new instance to ensure everything functions correctly.
4. Update DNS or endpoint references as needed, then decommission the old instance.

This process replicates your instance including all data and configurations on a new host, which may address any underlying physical server issues.

When relocating your Lightsail instance using a snapshot, you’ll be billed for the storage of snapshots and for running both old and new instances during migration. Remember to delete any unnecessary snapshots and instances promptly to control costs.