@lost Have you seen that there is a how-to-topic for the AVM DVB-C at [HowTo] Configure Tvheadend 4.2 and the Sat>IP Server AVM FRITZ!WLAN Repeater DVB-C on OSMC ?
I think this can be adapted for the AVM 6490 with 4 tuners, so you need 4 additional ipv4, in TVHeadend its DVB-C4 device, etc.