How do I used multiple variables

My query only works with All defaults, but not with non-defaults
How do I allow it to work with one or more variables?
Query:
traffic_congestion{Location=~"x${row}c${cabinet}r${switch}j${jack}"}

My data “Location” label format is:
x[0-9]+c[0-9]+s[0-9]+j[0-0]

Defined variables, all with a default of “.+”

Dropdown looks good with these Regex variables (from Prometheus data source)

  row=x(.+)c.+
  cabinet=x.+c(.+)r.+
  switch=x.+c.+r(.+)j.+
  jack=x.+c.+r.+j(.+)

I am not trying to use multiple values in a single variable