Why ppp0 is reported as both connected and disconnected?

I have an Ubuntu 21.10 and I get the below confusing network status related to ppp0; RDS (aka StamAcasa.rdsne) is the name of my network connection providing access to Internet.

Why ppp0 is reported as disconnected by nmcli device but connected by ifconfig? How should I fix this?

$nmcli device
DEVICE           TYPE      STATE                   CONNECTION      
eno1             ethernet  connected               RDS             
enp2s0           ethernet  connected               enp2s0          
br-4d725814c237  bridge    connected               br-4d725814c237 
br-667e68774f98  bridge    connected (externally)  br-667e68774f98 
docker0          bridge    connected (externally)  docker0         
ppp0             ppp       disconnected            --              
lo               loopback  unmanaged               --              

$nmcli device show ppp0
GENERAL.DEVICE:                         ppp0
GENERAL.TYPE:                           ppp
GENERAL.HWADDR:                         (unknown)
GENERAL.MTU:                            1492
GENERAL.STATE:                          30 (disconnected)
GENERAL.CONNECTION:                     --
GENERAL.CON-PATH:                       --

$ip link show | grep -i ppp
5: ppp0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1492 qdisc fq_codel state UNKNOWN mode DEFAULT group default qlen 3
    link/ppp 

$ifconfig | grep -A5 ppp
ppp0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1492
        inet 86.124.169.167  netmask 255.255.255.255  destination 10.0.0.1
        ppp  txqueuelen 3  (Point-to-Point Protocol)
        RX packets 64158  bytes 57421437 (57.4 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 33280  bytes 13396662 (13.3 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

$netstat -r
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
default         StamAcasa.rdsne 0.0.0.0         UG        0 0          0 ppp0
StamAcasa.rdsne 0.0.0.0         255.255.255.255 UH        0 0          0 ppp0
link-local      0.0.0.0         255.255.0.0     U         0 0          0 enp2s0
172.17.0.0      0.0.0.0         255.255.0.0     U         0 0          0 docker0
172.20.0.0      0.0.0.0         255.255.0.0     U         0 0          0 br-4d725814c237
172.29.0.0      0.0.0.0         255.255.0.0     U         0 0          0 br-667e68774f98
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 enp2s0
192.168.0.0     0.0.0.0         255.255.255.0   U         0 0          0 enp2s0
192.168.31.0    0.0.0.0         255.255.255.0   U         0 0          0 enp2s0

$ping www.google.com
PING www.google.com (172.217.19.100) 56(84) bytes of data.
64 bytes from bud02s27-in-f4.1e100.net (172.217.19.100): icmp_seq=1 ttl=59 time=33.3 ms
64 bytes from muc03s07-in-f100.1e100.net (172.217.19.100): icmp_seq=2 ttl=59 time=33.5 ms

$lspci | grep -i eth
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (7) I219-V (rev 10)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)