Recently I open process monitor and find snowflake is connecting to node inside my country, this may affect privacy, how to make snowflake not connecting this node(I worry this is a malicious node in my country, even if not, this is not a good idea because ISP can see entry guard definitely.)?
I believe what you wnat is ExcludeNodes in your torrc file
I keep a bookmark to this man page even though I use Windows. I know there is a link from the Tor site but could not find it. It should be the same.
Search for the entry ExcludeNodes node,node and read it also do not forget tot read the entry for StrictNodes 0|1
So to exclude France from the node use
ExcludeNodes {fr}
Your ISP will still see you connect to the guard node wherever that is. Even if using a VPN the ISP will see a connection to the VPN.