Hello@mgrouch

LVGL is a good GUI.
LVGL(Light and Versatile Graphics Library)
https://lvgl.io/
LVGL always evolves and requires a description that suits Version.

How to run LVGL on M5Stack : v7.11.0
https://forum.m5stack.com/topic/3613/how-to-run-lvgl-on-m5stack

How to run LVGL on M5Stack ( ESP32 )
https://macsbug.wordpress.com/2021/06/

LVGL with M5Stack Part 2
https://macsbug.wordpress.com/2021/07/03/lvgl-with-m5stack-part-2/

CO2 monitor with M5Stack and LVGL
https://macsbug.wordpress.com/2021/07/05/co2-monitor-with-m5stack-and-lvgl/

Hello@theMusicMan

M5Stack Core2 uses:

m5stack/M5Core2
https://github.com/m5stack/M5Core2

Hello@aezero

There is SD-Updater as a way to flash with .bin.

lovyan03/M5Stack_LovyanLauncher
Application startup by SD-Updater
https://github.com/lovyan03/M5Stack_LovyanLauncher

Youtube : M5Stack Lovyan Launcher - Ultimate Menu System
https://www.youtube.com/watch?v=2MyFKLZKJ2A

：
M5Stack-SD-Updater : 2018.03.12
https://macsbug.wordpress.com/2018/03/12/m5stack-sd-updater/
：
Github : tobozo/M5Stack-SD-Updater
https://github.com/tobozo/M5Stack-SD-Updater
Youtube : tobozo tagada : M5Stack Apps loaded from SD Card
https://www.youtube.com/watch?time_continue=13&v=myQfeYxyc3o

Hello@margel

The description in m5-docs is done with setTextColor.

https://github.com/m5stack/m5-docs/blob/master/docs/en/api/lcd.md
setTextColor( color, backgroundcolor )

Hello@caccum

M5Stack Core2　初期化(工場出荷状態に)してみた
M5Stack Core2 I tried to initialize (factory settings)
https://w-tori.net/wp/m5stack-core2-reset/

M5Stack Core2を工場出荷時のファームに戻す
Restore M5Stack Core2 to Factory Farm
https://qiita.com/Toshiaki0315/items/407cd7b0ed87f7f50617

Hello@jerome83136

Make using the following products.

Smart Food Dispenser Pets New Inventions Cat Puppy Timing Feeder Microchip Rfid Automatic Dog Plate

https://www.alibaba.com/product-detail/Smart-Food-Dispenser-Pets-New-Inventions_1600508280273.html

https://www.aliexpress.com/item/1005004305910681.html

https://www.aliexpress.com/item/1005004313818854.html

Hello@admiralmaggie

It depends on the type of HDMI Display.

Not Display Module 13.2, but...
For ATOM Display and TOSHIBA REGZA：
(1920/4,1080/4,24);
(640,360,60);
(320,180,60,1280,720);
(320,240,60,3204,2403);
(500,300,60,1280,720);
(500,300,24,1920,1080);
(480,320,24,1920,1080);
(480,320,60,1280,720);
(500,300,60,1280,720);

Hello@João Rodrigues

tobozo/M5Stack-SD-Updater
https://github.com/tobozo/M5Stack-SD-Updater

M5Stack-SD-Updater
https://macsbug.wordpress.com/2018/03/12/m5stack-sd-updater/

lovyan03/M5Stack_LovyanLauncher
https://github.com/lovyan03/M5Stack_LovyanLauncher

LovyanLauncher
https://twitter.com/lovyan03/status/1127119598602448896