In RHEL8 the old network scripts have been deprecated. However, if you want you can addd them back in.

Red Hat have provided them in a package called network-scripts

$ sudo yum install network-scripts.x86_64

This adds all your favourite scripts back in

$ sudo rpm -ql network-scripts
/etc/rc.d/init.d/network
/etc/sysconfig/network-scripts
/etc/sysconfig/network-scripts/ifcfg-lo
/etc/sysconfig/network-scripts/ifdown
/etc/sysconfig/network-scripts/ifdown-bnep
/etc/sysconfig/network-scripts/ifdown-eth
/etc/sysconfig/network-scripts/ifdown-ippp
/etc/sysconfig/network-scripts/ifdown-ipv6
/etc/sysconfig/network-scripts/ifdown-isdn
/etc/sysconfig/network-scripts/ifdown-post
/etc/sysconfig/network-scripts/ifdown-routes
/etc/sysconfig/network-scripts/ifdown-sit
/etc/sysconfig/network-scripts/ifdown-tunnel
/etc/sysconfig/network-scripts/ifup
/etc/sysconfig/network-scripts/ifup-aliases
/etc/sysconfig/network-scripts/ifup-bnep
/etc/sysconfig/network-scripts/ifup-eth
/etc/sysconfig/network-scripts/ifup-ippp
/etc/sysconfig/network-scripts/ifup-ipv6
/etc/sysconfig/network-scripts/ifup-isdn
/etc/sysconfig/network-scripts/ifup-plip
/etc/sysconfig/network-scripts/ifup-plusb
/etc/sysconfig/network-scripts/ifup-post
/etc/sysconfig/network-scripts/ifup-routes
/etc/sysconfig/network-scripts/ifup-sit
/etc/sysconfig/network-scripts/ifup-tunnel
/etc/sysconfig/network-scripts/ifup-wireless
/etc/sysconfig/network-scripts/init.ipv6-global
/etc/sysconfig/network-scripts/network-functions
/etc/sysconfig/network-scripts/network-functions-ipv6
/usr/lib/.build-id
/usr/lib/.build-id/df
/usr/lib/.build-id/df/fce1383c3b10c1e20c4e4684d16a35c65cad1d
/usr/sbin/ifdown
/usr/sbin/ifup
/usr/sbin/usernetctl
/usr/share/doc/network-scripts
/usr/share/doc/network-scripts/examples
/usr/share/doc/network-scripts/examples/ifcfg-bond-802.3ad
/usr/share/doc/network-scripts/examples/ifcfg-bond-activebackup-arpmon
/usr/share/doc/network-scripts/examples/ifcfg-bond-activebackup-miimon
/usr/share/doc/network-scripts/examples/ifcfg-bond-slave
/usr/share/doc/network-scripts/examples/ifcfg-bridge
/usr/share/doc/network-scripts/examples/ifcfg-bridge-port
/usr/share/doc/network-scripts/examples/ifcfg-eth-alias
/usr/share/doc/network-scripts/examples/ifcfg-eth-dhcp
/usr/share/doc/network-scripts/examples/ifcfg-vlan
/usr/share/doc/network-scripts/examples/static-routes-ipv6
/usr/share/doc/network-scripts/sysconfig.txt
/usr/share/man/man8/ifdown.8.gz
/usr/share/man/man8/ifup.8.gz
/usr/share/man/man8/usernetctl.8.gz

Feedback welcome as always!