just adding the -F to the default sysconfig file wont help to update existing
sysconfig files.

you could use sysconf_addword for it but tbh those options could also be
directly in the service file and the sysconfig file would document that these
options are *always* set.

furthermore an upstream dev recommended to just use the upstream service files
from
https://git.samba.org/?p=samba.git;a=commitdiff;h=8b6f58194da7e849cdb9d20712dff49b17a93a77

as the process group cmdline option is also important.