There should be at least a console accessible since Android use the linux kernel.
Why is there no terminal emulator or console installed by default in Android OS ?
Is there a particular reason?
Terminal emulator is a developer level app which is not a highly usable app for general users there is no need for mobile manufactures to load this app at the time of manufacturing. also terminal emulator is not highly efficient as original terminal of linux.
Even in desktop variant of linux not every user have the hang of terminal other than some basic commands.
Use the Android Debug Bridge (https://developer.android.com/studio/command-line/adb.html) It's on the PC and you need to connect it. I think it's not necessary to have a "Terminal APP". For tasks wich need root privilegues, you also need to root the phone.