Adding a delay to all network traffic is pretty easy and can be done through the following command.
adding a delay
#for device enp0s3
tc qdisc add dev enp0s3 root netem delay 100ms
query the current delay
#for all devices
tc -s qdisc
#for device enp0s3
tc qdisc show dev enp0s3
removing the delay
tc qdisc del dev enp0s3 root netem