Reports: Map Filters: Use field as variable in where clause?

[AlfredBaldenweck]

Map expressions—ArcGIS Survey123 | Documentation

I'm trying to use a map question in my report. In it, I'm attempting to filter down layer 3 where its field "grnduuid" is equal to this survey's inspuuid.

Here is an attempt:

${$map | map: “3d6eb5778a174e55ad2a1a75783eeade” | mapFilters: “’196ef2e95d0-layer-3’: where=grnduuid=inspuuid”}

Here is another:

${$map | map: “3d6eb5778a174e55ad2a1a75783eeade” | mapFilters: “’196ef2e95d0-layer-3’: where=grnduuid=SURVEY_TABLE.inspuuid”}

Here is another (failed in syntax check)

${$map | map: “3d6eb5778a174e55ad2a1a75783eeade” | mapFilters: “’196ef2e95d0-layer-3’: where=grnduuid=${inspuuid}”}

ditto for 

${$map | map: “3d6eb5778a174e55ad2a1a75783eeade” | mapFilters: “’196ef2e95d0-layer-3’: where=grnduuid=@inspuuid”}

What gives?

How can I call a variable in a where clause?