Two bar charts aggregated

Hello,
I have two bar charts, one showing heating gas consumption and theother DHW gas consumption:

from(bucket: "Baza")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "m³")
  |> filter(fn: (r) => r["friendly_name"] == "Zużycie gazu na ogrzewanie - dziś" or r["friendly_name"] == "E3_Vitodens_200_0421 Heating gas consumption current day")
  |> filter(fn: (r) => r["source"] == "HA")
  |> filter(fn: (r) => r["_field"] == "value")
  |> filter(fn: (r) => r["domain"] == "sensor")
  |> aggregateWindow(every: 1d, fn: max)
  |> yield(name: "last")
from(bucket: "Baza")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "m³")
  |> filter(fn: (r) => r["_field"] == "value")
  |> filter(fn: (r) => r["domain"] == "sensor")
  |> filter(fn: (r) => r["entity_id"] == "vicare_hot_water_gas_consumption_current_day" or r["entity_id"] == "vicare_hot_water_gas_consumption_today")
  |> aggregateWindow(every: 1d, fn: max)
  |> yield(name: "last")

Now, how to achieve something like this in FLUX?
A common bar for both heating gas and DHW gas, DHW gas being on top of heating gas,

In the flux documentation look for union