FWIW,
Have not used Fusion for the mill / router but for the lathe module, relative to the posting of the G28..........
I have not found anywhere, other than changing the post processor, that will change the posting of the G28.
Changing the conditions of the parameter Go Home under Compare and Edit for example, the G28 still gets posted
at the beginning and end.
I don't recommend changing the post processor unless you understand where, why and how it should be done.
There are a few videos about understanding / navigating the post processor.
RICH