Can I use another port than 7070 for the FNE server

Yes, this is possible since FNE software 2022.04.0.0/2019.07.1.0-22144. You can change the port in file /etc/systemd/system/advantest-fne-server.service.d/flexnetls-socbu.conf, entry Environment=PORT=7070.

Note: you need to take care that the new port is also opened in the firewall of the server.