Raspberry Pi Pico/TFT_eSPI display on 3.5" 480 x 320 ILI9488 SPI TFT

This video show Raspberry Pi Pico (RP2040) using TFT_eSPI library display on 3.5" 480 x 320 ILI9488 SPI TFT, in Arduino Framework.

Install TFT_eSPI in Arduino IDE's Library Manager. It's strongly suggested to visit TFT_eSPI page, scroll down to Tips section.

If you load a new copy of TFT_eSPI then it will overwrite your setups if they are kept within the TFT_eSPI folder. One way around this is to create a new folder in your Arduino library folder called "TFT_eSPI_Setups".
You then place your custom setup.h files in there.
After an upgrade simply edit the User_Setup_Select.h file to point to your custom setup file.

To locate Arduino library folder:
> File > Preferences...

Copy the path inside Sketchbook location. Open file explorer to open Sketchbook location, to locate Arduino library folder.

Create a new folder in your Arduino library folder called "TFT_eSPI_Setups".

Copy the file /TFT_eSPI/User_Setups/Setup21_ILI9488.h (it's checked to work in my case) to the new created TFT_eSPI_Setups folder. Rename it what you want, myTFT_eSPI_Setups_pico.h.

Edit the User_Setup_Select.h file to point to your custom setup file:
#include <../TFT_eSPI_Setups/myTFT_eSPI_Setups_pico.h>

Edit the custom setup.h file (myTFT_eSPI_Setups_pico.h) to match our connection.

#define TFT_MISO 	16	// (leave TFT SDO disconnected if other SPI devices share MISO)
#define TFT_MOSI	19
#define TFT_SCLK	18
#define TFT_CS    	17	// Chip select control pin
#define TFT_DC    	20	// Data Command control pin
#define TFT_RST		21	// Reset pin (could connect to RST pin)

Then you can try TFT_eSPI examples.