Gigabyte B550m PCIe lanes?

Hi. I've put together a pc which I'm using as a test server/PC but think I've run out of PCIe lanes.

I tried adding a PCIe to m2 card and it disabled one m2 and some sata HDDs when installed.

I plan to move the sata HDDs out into a nas and would like to install a PCIe Ethernet 2.5gb card but can't figure out if it will work.

Can anyone take a look and advice on if its a pci lane issue please.

Specs, Gigabyte B550m DS3H rev 1.1 AMD 5600G Processor 2 x M2 nvme ssd 4 x RAM PCIe (2.0 x4) dual ethernet card 4 x SATA HDD 1 x usb HHD

Thanks!