我已阅读了之前对这个问题的回答。它们对我没有帮助，因为我似乎收到了相互矛盾的信号。下面重现了各种命令的输出。
<------------ 输出粘贴在下面 ------------->
Desktop$ grep -i renderer /etc/netplan/*.yaml
/etc/netplan/00-default-nm-renderer.yaml: renderer: NetworkManager
/etc/netplan/01-network-manager-all.yaml: renderer: NetworkManager
Desktop$ service --status-all | grep -i net
Desktop$ sudo service network-manager status
Unit network-manager.service could not be found.
Desktop$ sudo service systemd-networkd status
● systemd-networkd.service - Network Service
Loaded: loaded (/lib/systemd/system/systemd-networkd.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:systemd-networkd.service(8)
Desktop$ ps aux | grep network-manager
root 831 0.0 0.0 393544 15900 ? Ssl 11:02 0:01 /snap/network-manager/653/usr/sbin/NetworkManager --config-dir=/var/snap/network-manager/653/conf.d/ --config=/snap/network-manager/653/etc/NetworkManager/NetworkManager.conf --log-level=INFO --no-daemon
xxxxx+ 4521 0.0 0.0 17676 2636 pts/0 S+ 11:57 0:00 grep --color=auto network-manager
Desktop$ dpkg --get-selections | grep network-manager
Desktop$ sudo systemctl start NetworkManager.service
Failed to start NetworkManager.service: Unit NetworkManager.service not found.
Desktop$ systemctl list-units | grep -i net
sys-devices-pci0000:00-0000:00:1c.0-0000:01:00.0-net-enp1s0.device loaded active plugged I211 Gigabit Network Connection
sys-devices-pci0000:00-0000:00:1c.4-0000:02:00.0-net-enp2s0.device loaded active plugged I211 Gigabit Network Connection
sys-devices-virtual-net-docker0.device loaded active plugged /sys/devices/virtual/net/docker0
sys-subsystem-net-devices-docker0.device loaded active plugged /sys/subsystem/net/devices/docker0
sys-subsystem-net-devices-enp1s0.device loaded active plugged I211 Gigabit Network Connection
sys-subsystem-net-devices-enp2s0.device loaded active plugged I211 Gigabit Network Connection
run-snapd-ns-network\x2dmanager.mnt.mount loaded active mounted /run/snapd/ns/network-manager.mnt
snap-network\x2dmanager-653.mount loaded active mounted Mount unit for network-manager, revision 653
networkd-dispatcher.service loaded active running Dispatcher daemon for systemd-networkd
snap.network-manager.networkmanager.service loaded active running Service for snap application network-manager.networkmanager
systemd-resolved.service loaded active running Network Name Resolution
systemd-timesyncd.service loaded active running Network Time Synchronization
network-online.target loaded active active Network is Online
network.target loaded active active Network
nss-lookup.target loaded active active Host and Network Name Lookups
<-----------------输出结束-------------------------->