Controlling Android phone with Termux or any other platform (Windows, Mac, or Linux) is very easy because of a tool called ScrCpy (Screen Copy). This tool use adb to connect with the device and allows you to control the whole Android phone remotely.
Installing ScrCpy
ScrCpy tool is available for all platform and now it is also available on Termux, So here I will be do this in Termux and also Kali Nethuner same way you can install it on any debian based linux distro like Ubuntu
First we need to update repository
pkg update
Now install Scrcpy and also adb
pkg install x11-repo -y ; pkg install -y android-tools scrcpy
Next we need to connect to the Android phone via adb, as we doing this in Termux we can use wireless debugging method (works only on Android 11 or greater).
So first we need to enable developed option, for that go to your setting app and go to About and click 7 times on build number after that you will see a message that "you are now a developer".
Next go to System -> developer options and click on wireless debugging and enable it, then click on pair with pairing code. It will give you a ip:port and pairing code, Then go to Termux and execute
adb pair <ip address>:<port>
in above command change the ip address and port with the ip and port shown when you clicked on pair with pairing code, After that it will ask for pairing code, just enter it.
Next we need to connect to the device
adb connect < your ip address>:<port>
Change ip and port which is shown on wireless debugging page.
Execute following to check whether the device is connected or not
adb devices
Now to use this tool you need to GUI installed, if you don't have watch this video 👇
Then Just start your vncserver
vncserver
And connect to it
Then open your terminal, and execute following to start ScrCpy
scrcpy