Including all & null values in query variable when showing All using Elasticsearch

I’m currently trying to create a query variable that includes all values but also null values when using the All option.
We have a field method. This method can pass through multiple environments. However, the environment field is only populated when it passes through specific environments, with all other ones leaving the field empty. I want to be able to show all environments (including the ones that leave the field empty) using the All option, while still using a variable to filter for the environments that populate the field.

I’ve worked my way through things referenced in the Elasticsearch documentations here Query string query | Elasticsearch Guide [7.16] | Elastic including fiddling around with _missing_ and _exists_, but have been unable to come up with a solution. I unfortunately also can’t find another thread presenting the same problem, so any help is greatly appreciated.

Grafana version is 8.3.2 using OSS Grafana.