Cannot connect to internet after fresh install of debian

Question

So , yesterday I did a fresh install of Debian 11 on my Dell Vostro 3480 , I got a DHCP issue during the configuration so I entered the IP and mask manually during at that time .

After that once the installation got completed , I was able to see that I wasn't getting any icon of wi-fi or I was not able to connect to my home modem .

I did the following :

lspci output

01:00.0 Ethernet Controller: Realtek Semiconductor Co. , Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
02:00.0 Network Controller: Qualcomm Atheros QCA9377 802.11ac Wireless Network Adapter (rev 31)

ifconfig

bash: ifconfig: command not found

ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
    valid_lft forever preferred_lft forever 
   inet6 ::1/128 scope host 
    valid_lft forever preferred_lft forever 
2: enpls0:  <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
    link/ether d8:d0:50:44:76:6d brd ff:ff:ff:ff:ff:ff 

route -n

bash: route: command not found

ip route

[Nothing is shown]

I was able to see similar issues were posted earlier on here , and i referred those threads completely

So , I download the firmware-iwlwifi file from here on my usb drive and then i mounted the file to another directory using the below command

sudo mount /dev/sdb1 /media/usb

After this , I went under /etc/apt/sources.list and added "non-free" at the end of the below predefined lines so it looked something like this :

deb http://security.debian.org/debian-security bullseye-security main contrib non-free
deb-src http://security.debian.org/debian-security bullseye-security main contrib non-free

After this , I went into /media/usb and then ran the below command

sudo dpkg -i firmware-iwlwifi_20210315-3_all.deb

Selecting previously unselected package firmware iwlwifi
(Reading database ... 143298 files and directories currently installed.)
Preparing to unpack firmware-iwlwifi_20210315-3_all.deb ...
Unpacking firmware-iwlwifi (20210315-3) ...
Setting up firmware-iwlwifi (20210315-3) ...

sudo apt-get install firmware-iwlwifi

Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
firmware-iwlwifi is already the newest version (20210315-3).
0 upgraded , 0 newly installed , 0 to remove and 0 not upgraded .

After this when I reboot my device (as it is recommended) and then when I log back in again and then when i type the below command :

lsmod | grep iwl

[Nothing comes up]

After this , when I type the below command , I'm able to see the NetworkManager is up .

sudo systemctl status NetworkManager

NetworkManager.service - Network Manager
    Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; vendor preset: enabled)
    Active: active (running) since Wed 2023-01-18 09:16:54 GMT; 35min ago
    Docs: man:NetworkManager(8)
    Main PID: 594 (NetworkManager)
    Tasks: 3 (limit: 9322)
    Memory: 13.0M
    CPU: 721ms 
    CGroup: /system.slice/NetworkManager.service
          594 /usr/bin/NetworkManager --no-daemon

I am quite stuck on this issue right now , Any suggestion or help regarding this would extremely helpful . As , currently it's not possible to access internet from this machine right now .

Thank you !