N
For anyone encountering this issue, here's a workaround workflow that abandons symbols and uses styled groups, object markers and transform each:
Instead of making a symbol out of a deeply nested group
mark the group
open the "Selections" panel
click on the hamburger menu
select "Setup Markers"
create a marker
select the group
Select Menu > Markers > Object Marker > Choose marker
either
clone it ( currently to be avoided until bugs are fixed by @vectoradmin )
just make copies of it and rely on the nested styles for uniformity
Select Menu > Markers > Select Marker > Choose marker
all marked objects are selected
Object Menu > Transform > Scale > check "Transform Each" > select reference point > scale
The benefit here is, as discussed above with @vectoradmin, that you now have symbol-like capabilities ( although using more memory as a disadvantage ) and can also use not only this better scaling, but make targeted overrides to some of multiple uses of the same style in deeply nested, styled groups.
