@Powersoft
Yes, you can find ESC sequence handling at lines 1515-1927 of Terminal.cpp.

I didn't implement those pins selectable in software because it is intended for use on almost any ESP-based hardware.
Though if I have a good idea on how to do it without sacrificing portability I might add it later.

@easytarget
It seems to me that the M5 team could've done a better job with the Tab5 schematics to avoid all this potential confusion.
Thanks for taking the time to point out all those details.

@Powersoft Hi!
I have updated the project and added a feature flag at line 26 of PlatformConfig.hpp. If you uncomment it the source compiles with grove connector as a UART.
As can be seen at TermTab.ino lines 136-137: pin 53 is TX and pin 54 is RX.
You are welcome.

@Powersoft Hi!
You can easily use any pins with SoftwareSerial, though I did not test it. One of my primary goals was to make it work fast (which is not what you usually expect from software serial).
Can you do it yourself? Or maybe use a GhatGPT (point it to the main .ino file and ask to change to pins you want).
If you encounter any problems message me, I'll try to find some time to do tests.

@easytarget I assume you did not read my message carefully. G1/G3 are in the PDF Schematics

@Powersoft Hi!
Not visiting this forum very often, I'd have to see if notifications can be enabled.

So, to your question, if you download Tab5 schematics there's M5_BUS connector on page 4. You need pins 13 (aka U0RXD, aka G3) and 14 (aka U0TXD, aka G1). They use 3V3 logic levels but are 5V tolerant as per Espressif themselves (and my thorough testing).
Feel free to ask more questions.

TermTab5 is an Arduino/ESP32 touchscreen terminal firmware project with a VT100-style terminal core, on-screen keyboard, touch-driven menu system, board abstraction layer, settings persistence, Wi-Fi helpers, and optional screensaver-style animations.

The codebase targets M5 Tab5 and related ESP32 display hardware, while keeping a substantial part of the terminal and UI stack reusable and host-testable.

GitHub repo

Demo video
In this video is a custom made Z80-based handheld retro computer running RomWBW with Tab5 as a screen.