Realtek RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet might work better if r8168 driver is used instead of r8169 driver
Manjaro hardware detection tool can install kernel modules for r8168 driver and blacklist r8169 driver
sudo mhwd -i pci network-r8168
Or use Manjaro Settings Manager GUI:
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
Wired connection keeps dropping
Network disconnects for a minute after sleep