NIC is using the driver r8169
Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Gigabyte driver: r8169
Gigabyte motherboards require the correct driver r8168 to work properly
suggest you change to r8168 driver with Manjaro Settings Manager
manjaro-settings-manager -m msm_mhwd
enable option in bottom left corner - Show All Devices
Look in section Network controller > RTL8111/8168/8411 for network-r8168
Right click on network-r8168 and select Install
Manjaro Settings Manager will install the driver for all installed kernel versions and create a blacklist command to prevent driver r8169 from loading