⟩ How to filter out the default route from outgoing BGP advertisements?
Assuming you have a static default route that is redistributed because redistribute-static parameter is set to yes, do the following:
/routing filter add chain=myfilter prefix=0.0.0.0/0 action=discard
Then set myfilter as the out-filter for BGP instance
/routing bgp instance set default out-filter=myfilter