network frame sync

Hello,
thanks a lot for libreelec , it works like a charm here.
i used to sync displays via omxplayer and osc udp , but made the change to be able to output 10 bits 4k H265 with aac audio.

i made shell scripts and am currently using kodi callbacks to link multiple players ,
but sync is soso , with high latency compared to what i had before.
any hints ?

did someone tried something in this area ?
Have a nice day.

Py

i wasn't very precise :
i am on a network of raspberry pi 4 with librelec 12.0.2 iirc
there is a router with dhcp on the network , but ip are fixed, and all machines are on the lan side of it.
i play local files that are on each pi, of synchronised loops
i get low values for ping ,

removed buffering , but still have a fluctuating start time ( different when pointer is displayed than when in "full screen"

thanks for any help. it would be a great anbd cheap solution for artists.