Wired network stopped working after I switched from Gnome to KDE Plasma and back. I got it working on Gnome earlier, switched to KDE and didn't use wired for some time, today I switched back to Gnome and it doesn't work.
$ sudo ethtool wlp2s0
Settings for wlp2s0:
Link detected: yes
$ sudo lshw -c net
*-network UNCLAIMED
description: Ethernet controller
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci@0000:01:00.0
version: 10
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix vpd cap_list
configuration: latency=0
resources: ioport:5000(size=256) memory:a4104000-a4104fff memory:a4100000-a4103fff
*-network
description: Wireless interface
product: RTL8821AE 802.11ac PCIe Wireless Network Adapter
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci@0000:02:00.0
logical name: wlp2s0
version: 00
serial: c8:3d:d4:3b:e9:71
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
configuration: broadcast=yes driver=rtl8821ae driverversion=5.15.0-57-generic firmware=N/A ip=192.168.1.129 latency=0 link=yes multicast=yes wireless=IEEE 802.11
resources: irq:128 ioport:4000(size=256) memory:a4000000-a4003fff
# apt list --installed | grep -E '^linux'
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
linux-base/focal-updates,focal-updates,now 4.5ubuntu3.7 all [installed,automatic]
linux-firmware/focal-updates,focal-updates,now 1.187.35 all [installed,automatic]
linux-generic-hwe-20.04/focal-updates,focal-security,now 5.15.0.58.64~20.04.24 amd64 [installed]
linux-headers-5.15.0-57-generic/focal-updates,focal-security,now 5.15.0-57.63~20.04.1 amd64 [installed]
linux-headers-5.15.0-58-generic/focal-updates,focal-security,now 5.15.0-58.64~20.04.1 amd64 [installed,automatic]
linux-headers-5.4.0-137-generic/focal-updates,focal-security,now 5.4.0-137.154 amd64 [installed,automatic]
linux-headers-5.4.0-137/focal-updates,focal-updates,focal-security,focal-security,now 5.4.0-137.154 all [installed,automatic]
linux-headers-generic-hwe-20.04/focal-updates,focal-security,now 5.15.0.58.64~20.04.24 amd64 [installed,automatic]
linux-headers-generic/focal-updates,focal-security,now 5.4.0.137.135 amd64 [installed]
linux-hwe-5.15-headers-5.15.0-57/focal-updates,focal-updates,focal-security,focal-security,now 5.15.0-57.63~20.04.1 all [installed,automatic]
linux-hwe-5.15-headers-5.15.0-58/focal-updates,focal-updates,focal-security,focal-security,now 5.15.0-58.64~20.04.1 all [installed,automatic]
linux-image-5.15.0-57-generic/focal-updates,focal-security,now 5.15.0-57.63~20.04.1 amd64 [installed]
linux-image-5.15.0-58-generic/focal-updates,focal-security,now 5.15.0-58.64~20.04.1 amd64 [installed,automatic]
linux-image-generic-hwe-20.04/focal-updates,focal-security,now 5.15.0.58.64~20.04.24 amd64 [installed,automatic]
linux-libc-dev/focal-updates,focal-security,now 5.4.0-137.154 amd64 [installed,automatic]
linux-modules-5.15.0-57-generic/focal-updates,focal-security,now 5.15.0-57.63~20.04.1 amd64 [installed]
linux-modules-5.15.0-58-generic/focal-updates,focal-security,now 5.15.0-58.64~20.04.1 amd64 [installed,automatic]
linux-modules-extra-5.15.0-57-generic/focal-updates,focal-security,now 5.15.0-57.63~20.04.1 amd64 [installed]
linux-modules-extra-5.15.0-58-generic/focal-updates,focal-security,now 5.15.0-58.64~20.04.1 amd64 [installed,automatic]
linux-sound-base/focal,focal,now 1.0.25+dfsg-0ubuntu5 all [installed,automatic]
# dkms status
nvidia, 525.78.01, 5.15.0-57-generic, x86_64: installed
nvidia, 525.78.01, 5.15.0-58-generic, x86_64: installed
nvidia, 525.78.01, 5.4.0-137-generic, x86_64: installed
rtl8821ce, 5.5.2.1, 5.15.0-57-generic, x86_64: installed
rtl8821ce, 5.5.2.1, 5.15.0-58-generic, x86_64: installed
rtl8821ce, 5.5.2.1, 5.4.0-137-generic, x86_64: installed
# grep r8169 /etc/modprobe.d/*
/etc/modprobe.d/r8168-dkms.conf:# map the specific PCI IDs instead of blacklisting the whole r8169 module
/etc/modprobe.d/r8168-dkms.conf:# to blacklist the whole r8169 module
/etc/modprobe.d/r8168-dkms.conf:#blacklist r8169
# dmesg | grep r8169
<no output>
# lspci -knn | grep Eth -A3
01:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 10)
Subsystem: Lenovo RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [17aa:384c]
Kernel modules: r8168
02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821AE 802.11ac PCIe Wireless Network Adapter [10ec:8821]
Subsystem: Lenovo RTL8821AE 802.11ac PCIe Wireless Network Adapter [17aa:a814]
