well,
the answer
to referecing an array by a name passed as variable (partly resemnbles pointer)
is different (example above reused):
eval echo "\$$(eval echo "{$gral[@]}")"
Result:
milk cow budgie pla9ne
YEAH!
took me much more than 10h net; this IS the answer. Thank you all for your attempts!
There are 2 hints leading to the result in abs-guide:
https://tldp.org/LDP/abs/html/abs-guide.html#IVR
and a remark by Emiliano G. in
https://tldp.org/LDP/abs/html/abs-guide.html#BRACEEXPREF3
OK,
eval is ugly due to security concerns.
Try to find a better one ...