1. Configure redsocks

/etc/redsocks.conf

base {
        log_debug = off;
        log_info = on;
        log = "syslog:local7";
        daemon = on;
        redirector = iptables;
}

redsocks {
        local_ip = 0.0.0.0;
        local_port = 1337;
        ip = socks-ip;
        port = socks-port;
        type = socks5;
        login = socks-username;
        password = socks-pass;
}

2. nftable chain/hook to redirect to redsocks

/etc/redsocks_fw.nft

chain REDSOCKS {
        # hook to the output/prerouting
        type nat hook prerouting priority dstnat; policy accept;

        # skip if the user is not uid 1000
        # ip protocol tcp skuid != 1000 return

        # skip for local ip ranges
        ip daddr 0.0.0.0/8      return
        ip daddr 10.0.0.0/8     return
        ip daddr 100.64.0.0/10  return
        ip daddr 127.0.0.0/8    return
        ip daddr 169.254.0.0/16 return
        ip daddr 172.16.0.0/12  return
        ip daddr 192.168.0.0/16 return
        ip daddr 198.18.0.0/15  return
        ip daddr 224.0.0.0/4    return
        ip daddr 240.0.0.0/4    return

        # do iptable redirect to redsocks port
        # e.g. redirect only internal ip .199 and .189
        ip protocol tcp ip saddr 192.168.1.199 redirect to 1337
        ip protocol tcp ip saddr 192.168.1.189 redirect to 1337
}

?. Add chain using fw4 (openwrt)

/etc/config/firewall

config include                             
        option  type            'nftables'
        option  path            '/etc/redsocks_fw.nft'
        option  position        'table-pre'     
        option  enabled         '1'                 
        option  chain           'dstnat' 

fw4 reload && service redsocks restart