Flex-table-card

1st post → “what can be shown in a row?”
Already suggested here that if a column must contain foo(x,y) where x,y - different attributes of same entity or attributes/states of different entities - then these data need to be a part of ONE attribute:

- data: Z
    modify: >-
      ... any JS code for Z.X & Z.Y
    name: any name

i.e. one attribute Z is a dictionary like:

{
  X: some data,
  Y: some data
}

For that you will need to create a template sensor.