Using KMS or Parameter Store values in a FRONTEND amplify app?

We are hosting a react app on amplify with no backend.

I see in the docs that you can use Parameter Store but it seems like that's only for backend applications?

https://docs.aws.amazon.com/amplify/latest/userguide/environment-variables.html#access-env-vars

Is there anyway to get these into a frontend application? Maybe during a build? These env vars are purely for the frontend and no a security concern.

This is tangentially related to using doppler for env variables. Basically, the vars are synced between doppler and parameter store, but now I'm unclear how to get them into the runtime or build for the frontend amplify application.

Also open to ideas how to get them straight from doppler into amplify, if there's a way to bypass parameters/KMS.