I did a fresh install of 18.0.4-stable and went for kernel 5.1
It used the r8168 by default. That driver entirely stalls after resuming from suspend, no more LAN networking and spewing kernel traces in the kernel log. Workaround is to modprobe -r and then load the module again.
There was no blacklisting set up for me under "/etc/modprobe.d/r8169_blacklist.conf"
I found this thread, removed the Realtek r8168 driver and successfully went for the kernel r8169 driver. No issues ever since.
Network: Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet driver: N/A
So as I understand, the r8169 driver is by far the bette choice for recent kernels.
I did not test installing with the developer ISO. Woud that be of help for you?