You can't pass MAXA() character strings directly (vs having a text value in a range of cells), but can pass numeric string such as "35". You can however pass non-numeric character strings as part of a range of cells (see example below) and it will assign them a value of zero.
The function will return something like
#NAME? as an error message if it cannot calculate the function parameters.
If you mouse over the value it returns in your example it will tell you why it failed.
Function MAXA parameter 4 expects number values.
But '#VALUE!' is a text and cannot be coerced to a number.
MAXA(3,4,"5") valid, it is a numeric string
MAXA(3,4,"five") invalid, as it is not a numeric string
MAXA(A1:A6) valid, "text" gets set to 0, when A1 to A6 looks like
A1 | -2
A2 | -4
A3 | -2
A4 | -5
A5 | -1
A6 | text
Source: the support document you linked.
Note they show in one of their examples that the result of
=MINA(A2:A6, "Google") is