RADIO_STATUS messages, buffer status in radio and fc

hi
i use pymavlink to exchange messages between gcs and companion.
when sending heartbeat on the gcs i get radio status messages on the gcs side ->fine
when sending heartbeat on the companion side i don’t get radio status messages.
does the fc eat the messages intentionally or it this a routing error?

my impression is that i can flood the pixracer message buffer without ardupilot/pixracer slowing down/halting the transmission from the (rpi) companion -> lost packets

how can i get information about the buffer state on the fc.
radio_status would give me information about the buffer state on the radio - if i would get the mesaages