Quartz scheduler properties not reading environment variables

I'm trying to pass in my environment variables similar to this question:Quartz properties file pass in environment variables

In my quartz.properties file

org.quartz.dataSource.db.user=$@DB_USERNAME

And then my Dockerfile:

ENV DB_USERNAME=test

However when I build and start my container, this is the error I am getting:

db_1   | 2022-09-14  9:24:15 18 [Warning] Access denied for user '${DB_USERNAME}'@'172.20.0.4' (using password: YES)

But If I replace my quartz.properties with the hardcoded value it works fine:

  org.quartz.dataSource.db.user=test

How can I use my environment variables with quartz.properties file?