I need to be able to change the units of measurement none/dollars
so that I can see raw data without rounding.
https://grafana.com/docs/grafana/latest/variables/templates-and-variables/
You can use variables in metric queries and in panel titles.
So you are trying to use variable in the config field, where it is unsupported. Use different approach which fits your needs e.g. two panels with different unit configuration, ...