Build-time secrets with UI deployments

How do i get access to secrets at build time when using the new UI deployment? I followed the guide of auto-inclusion of build secrets using ephemeral machines by having a a dockerfile for it but no information on how to integrate all that with the new Deployment UI.

I really need help with this because deploying from my terminal where the dockerfile path in my app config(fly.toml) is Dockerfile.builder fails because the secrets aren’t populated

I either get cat: can't open '/run/secrets/TURSO_DATABASE_URL': No such file or directory where dockerfile path is Dockerfile or deployment succeeds but app crashed when dockerfile path is Dockerfile.builder

Files used

Dockerfile.builder

Dockerfile

fly.toml

I can see that someone already made similar post but theirs is in regards to .npmrc