UART - duplicate or emulate signal

So, every arduino has an UART. What I would like is that you don’t have to worry how to connect TX or RX … I am really strugling on how to explain what I would like to ask.
So, basically, when the UART sends data, the TX light flickers (depending on the baud rate), is there a way to connect the TX to a digital input pin and read the voltage?
And vice versa, is there a way to set a digital output pin to high and hook it up to the RX pin of the UART? This makes sense?
Please indicate if you need more info.

is there a way to connect the TX to a digital input pin and read the voltage?

Yes. The voltage will be either 0 or 5V, so I'm not sure how much you'll learn from that.

And vice versa, is there a way to set a digital output pin to high and hook it up to the RX pin of the UART?

Yes.

This makes sense?

No.

Personally, I can't imagine anything simpler than connecting a USB cable to the Arduino and PC. Only one end of the cable fits the Arduino, and only one end fits the PC. So, it's pretty darn hard to get the cable wrong way around. The end that fits the Arduino only fits one way, so getting it upside or backwards just isn't possible. The same holds true for the PC end.

It's about as foolproof as you can get. Unlike your proposal...