you can "ban" the nodes you don't want to connect to. that is basically the manual version of what bitcoin core automatically does for bad nodes. the command name that you should use is
setban and the details of how to use it is as follows:
setban "subnet" "command" ( bantime absolute )
Attempts to add or remove an IP/Subnet from the banned list.
Arguments:
1. subnet (string, required) The IP/Subnet (see getpeerinfo for nodes IP) with an optional netmask (default is /32 = single IP)
2. command (string, required) 'add' to add an IP/Subnet to the list, 'remove' to remove an IP/Subnet from the list
3. bantime (numeric, optional, default=0) time in seconds how long (or until when if [absolute] is set) the IP is banned (0 or empty means using the default time of 24h which can also be overwritten by the -bantime startup argument)
4. absolute (boolean, optional, default=false) If set, the bantime must be an absolute timestamp in seconds since epoch (Jan 1 1970 GMT)
Examples:
> bitcoin-cli setban "192.168.0.6" "add" 86400
> bitcoin-cli setban "192.168.0.0/24" "add"
> curl --user myusername --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "setban", "params": ["192.168.0.6", "add", 86400] }' -H 'content-type: text/plain;' http://127.0.0.1:8332/
ref:
https://bitcoincore.org/en/doc/0.19.0/rpc/network/setban/