MINECRAFT JAVA EDITION on LAN: opensuse 15, not works

Minecraft uses TCP 25565 for communication, so you’ll need to open that port in your firewall on the system where you are hosting the minecraft server on.

You can open a port in firewall’s public zone by issuing:

sudo firewall-cmd  --zone=public --add-port=25565/tcp

It will ask for your root password. See if this helps, if not - let’s try to debug why not.