edit and copy-paste at the end of the file /etc/sysctl.conf

net.ipv4.tcp_no_metrics_save=1
net.core.rmem_default=65536
net.core.wmem_default=65536
net.core.rmem_max=52428800
net.core.wmem_max=52428800
net.ipv4.tcp_rmem = 8192 750000 52428800
net.ipv4.tcp_wmem = 8192 750000 52428800
net.ipv4.tcp_reordering=20
net.ipv4.tcp_timestamps=1
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_sack=0
net.ipv4.tcp_moderate_rcvbuf=1
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_adv_win_scale=9

save file, exit and reboot your machine 🙂

p.s. tnx to Popaj