How do I run 2 Android phones on a PC simultaneously So that DroidCam for number 1 & TC games screen mirror for number 2?
Applications like DroidCam or Scrcpy that require adb to work often include an own version of adb. For DroidCam you can see it in the sub-directory adb the three files that belong to adb:

adb.exe
AdbWinApi.dll
AdbWinUsbApi.dll

However adb is designed to be present one time on a system because when it starts it remains loaded invisible in the background.
Now if a program has it's own adb version it prefers this versions and therefore when it starts it's own adb version the previous adb daemon running background is killed and replaced with the different adb version.
In your case the message adb server is out of date. additionally indicates that you have two different versions of adb installed and the newer version kills the older version that was already running (old version = out of date version).
Some programs like Scrcpy allow to specify via environment variable where adb.exe is located so that you can redirect it to one adb versions that is available on your system.
I am not sure if DroidCam also supports such an environment variable.
But in any way you should &quot;equalize&quot; all adb versions you have installed:

Search your system where it has adb.exe installed
On each found adb.exe execute adb.exe --version and identify the newest version (the version installed with Android Studio shows at the moment Android Debug Bridge version 1.0.41 - Version 30.0.2-6538114
From the newest adb version copy the three files adb.exe, AdbWinApi.dll and AdbWinUsbApi.dll to the other locations adb.exe was found overwriting the existing files.

This should at least solve your problem that the adb versions installed have a different version.