Run top instead of getty

I don't think you can do it on tty6 because:

tty6 is especially reserved for auto-spawned gettys and unavailable to other subsystems such as X[3]. This is done in order to ensure that there's always a way to get a text login, even if due to fast user switching X took possession of more than 5 VTs.

For more info you can check here.

But you can try this on tty5 for example. You can create following service (testo.service or whatever you decide) in /lib/systemd/system/ on most distributions but in openSUSE I think it is /usr/lib/systemd/system:

[Unit]
Description=top on tty5

[Service]
Type=simple
ExecStart=/usr/bin/top
ExecStop=/bin/kill -HUP ${MAINPID}
StandardInput=tty
StandardOutput=tty
TTYPath=/dev/tty5
Restart=always
RestartSec=2

[Install]
WantedBy=getty.target

And then:

systemctl enable testo.service