SteveBromwich recommended some IP tuning:
echo 6000 > /proc/sys/net/core/netdev_max_backlog echo 3000 > /proc/sys/net/core/netdev_budget
ifconfig enp1s0 indicated
cat /proc/sys/net/ipv4/tcp_mem 22593 30124 45186
sysctl -w net.ipv4.tcp_timestamps=0 sysctl -w net.ipv4.tcp_sack=1 sysctl -w net.core.netdev_max_backlog=250000 sysctl -w net.ipv4.tcp_low_latency=1
...
ip route change default via 5.39.78.254 dev enp1s0 cwnd 100 initcwnd 100 ip link set txqueuelen 3000 dev enp1s0