Is there a Windows 10 Hotkey or Shortcut for switching to a specific display?

The built-in DisplaySwitch.exe tool can emulate the + P capabilities. You can potentially create four desktop shortcuts so that you have one available for each option:

For the PC screen only: %windir%\System32\DisplaySwitch.exe /internal

For Duplicate: %windir%\System32\DisplaySwitch.exe /clone

For Extend: %windir%\System32\DisplaySwitch.exe /extend

For Second screen only: %windir%\System32\DisplaySwitch.exe /external

(Source)

+ P toggles three modes:

1. Local only
2. Local + External (TV) -- duplicated
3. Local + External (TV) -- extended

My advise is to leave things set at #3 most of the time.

In this mode, all of your screens are always available. The keyboard will use whatever has the focus, regardless of which display you're looking at, and the mouse cursor will easily move back and forth.

That would still be a hassle, except you can also easily move individual programs between displays using these shortcuts:

+ Shift + (right arrow)
+ Shift + (left arrow)

So you can queue up something on your internal display, and then easily push it to the TV without losing access to the internal display.

If the left and right arrows seem backwards from your actual setup, you can adjust the monitor layout in display properties.