I am building a script for work where I have to scrape massive IP addresses, something like 50 million.
However, when analyzing my program and machine performance, we notice the following:

At least 10k of sockets went directly on TIME WAIT mode, without even being allocated.
Only 2k of sockets were used.
I tried editing kernel flags:

# Expand the range of ephemeral ports
sysctl -w net.ipv4.ip_local_port_range="10768 65535"

# Enable TCP Fast Open
sysctl -w net.ipv4.tcp_fastopen=3

# Increase socket buffer sizes
sysctl -w net.ipv4.tcp_rmem="4096 87380 6291456"
sysctl -w net.ipv4.tcp_wmem="4096 16384 4194304"

# Optimize keepalive settings -> in our case I think we don't care because we
# are talking about handshakes so we shouldn't have keepalive, but we never know
sysctl -w net.ipv4.tcp_keepalive_intvl=10
sysctl -w net.ipv4.tcp_keepalive_probes=3

# Increase maximum file descriptors
ulimit -n 1048576
echo "* soft nofile 1048576" >> /etc/security/limits.conf
echo "* hard nofile 1048576" >> /etc/security/limits.conf

# Increase TCP backlog
sysctl -w net.ipv4.tcp_max_syn_backlog=1024
# sysctl -w net.core.somaxconn=1024
# Enable advanced F-RTO
# sysctl -w net.ipv4.tcp_frto=2
sysctl -w net.ipv4.tcp_frto=0

# Reduce the number of orphan retries
sysctl -w net.ipv4.tcp_orphan_retries=1

# Set initial number of retransmissions before aggressive timing is used
sysctl -w net.ipv4.tcp_retries1=2

# Set maximum number of retransmissions before giving up
sysctl -w net.ipv4.tcp_retries2=8

# Reduce SYN-ACK retries
sysctl -w net.ipv4.tcp_synack_retries=2
# Reduce SYN-ACK retries
sysctl -w net.ipv4.tcp_syn_retries=2

# Reduce TCP connection timeouts
sysctl -w net.ipv4.tcp_fin_timeout=6

# Enable SYN cookies
sysctl -w net.ipv4.tcp_syncookies=1

# Set a moderate limit for TIME_WAIT sockets
sysctl -w net.ipv4.tcp_max_tw_buckets=10000

The only relevant flag that changed something was:

# Reduce TCP connection timeouts
sysctl -w net.ipv4.tcp_fin_timeout=6

But it only changed the duration of time wait sockets ; not the fact that only few were allocated.
What can I do ?
Should I use raw sockets ? (snif)