setting domainMax by determining the max of filtered datasets

I´m using the Deneb PowerBi visual, displaying a Population Pyramid for male / female

currently I´m defining the maxdomain of the axis by aggregating the whole (male+femal) numbers, which works, but isnt optimal:

I´d like to set the max domain by determining the max from male or female, so the available display space is optimal used

{
"data": {"name": "dataset"},
"transform": 
[
{
"calculate": "datum.Geschlecht == 'männlich' ? 'männlich' : 'weiblich'",
"as": "gender"
},
{
"joinaggregate": [{
"op": "sum",
"field": "KPI-Set Display",
"as": "MaxVal"
}]
}
],
"spacing": 0,
"hconcat": 
[
{
"transform": 
[
{
"filter": 
{
"field": "gender",
"equal": "weiblich"
}
}
],
"title": "",
"mark": 
{
"type": "bar",
"tooltip": true
},
"encoding": 
{
"y": 
{
"field": "Altersgruppe",
"axis": null,
"sort":
{
"field":"Sortierung",
"order":"descending"
}
},
"x": 
{
"aggregate": "sum",
"field": "KPI-Set Display",
"title": "weiblich & unbekannt",
"scale": {"domainMax":{"expr":"data('data_0')[0].MaxVal"}},
"axis": 
{
"format": "s"
},
"sort": "descending"
}
}
},
{
"width": 20,
"view": 
{
"stroke": null
},
"mark": 
{
"type": "text",
"align": "center"
},
"encoding": 
{
"y": 
{
"field": "Altersgruppe",
"type": "ordinal",
"axis": null,
"sort":
{
"field":"Sortierung",
"order":"descending"
}
},
"text": 
{
"field": "Altersgruppe",
"type": "nominal"
}
}
},        
{
"transform": 
[
{
"filter": 
{
"field": "gender",
"equal": "männlich"
}
}
],
"title": "",
"mark": 
{
"type": "bar",
"tooltip": true
},       
"encoding": 
{
"y": 
{
"field": "Altersgruppe",
"axis": null,
"sort":
{
"field":"Sortierung",
"order":"descending"
}
},
"x": 
{
"aggregate": "sum",
"field": "KPI-Set Display",
"title": "männlich",
"scale": {"domainMax":{"expr":"data('data_0')[0].MaxVal"}},
"axis": 
{
"format": "s"
},
"sort": "ascending"
}
}        
}
]
}

Is this what you're after?

{
"$schema": "https://vega.github.io/schema/vega-lite/v5.json",
"description": "A population pyramid for the US in 2000.",
"data": {"url": "data/population.json"},
"transform": [
{"filter": "datum.year == 2000"},
{"calculate": "datum.sex == 2 ? 'Female' : 'Male'", "as": "gender"},
{
"aggregate": [{"op": "sum", "field": "people", "as": "people"}],
"groupby": ["age", "gender"]
},
{"joinaggregate": [{"op": "max", "field": "people", "as": "MaxVal"}]}
],
"spacing": 0,
"hconcat": [
{
"transform": [{"filter": {"field": "gender", "equal": "Female"}}],
"title": "Female",
"mark": "bar",
"encoding": {
"y": {"field": "age", "axis": null, "sort": "descending"},
"x": {
"type": "quantitative",
"field": "people",
"title": "population",
"axis": {"format": "s"},
"scale": {"domainMax": {"expr": "data('source_0')[0].MaxVal"}},
"sort": "descending"
},
"color": {
"field": "gender",
"scale": {"range": ["#675193", "#ca8861"]},
"legend": null
}
}
},
{
"width": 20,
"view": {"stroke": null},
"mark": {"type": "text", "align": "center"},
"encoding": {
"y": {
"field": "age",
"type": "ordinal",
"axis": null,
"sort": "descending"
},
"text": {"field": "age", "type": "quantitative"}
}
},
{
"transform": [{"filter": {"field": "gender", "equal": "Male"}}],
"title": "Male",
"mark": "bar",
"encoding": {
"y": {
"field": "age",
"title": null,
"axis": null,
"sort": "descending"
},
"x": {
"type": "quantitative",
"field": "people",
"title": "population",
"axis": {"format": "s"},
"scale": {"domainMax": {"expr": "data('source_0')[0].MaxVal"}}
},
"color": {"field": "gender", "legend": null}
}
}
],
"config": {"view": {"stroke": null}, "axis": {"grid": false}}
}