Read serial data from unknown source using Raspberry pi
The protocol used for the communication with the LCD controller chips is I2C. It can't be received with an UART like you are now trying. You would need a special I2C logger tool or logic analyser to analyze it. Fortunately the RPi has I2C master interface so you could use it for talking to the LCD controller chips. Even an oscilloscope would help you to look at the waveforms, but if you can trace the I2C interface pins and understand the LCD controller datasheet how to initialize and use it, it might work, but many initialization parameters depend on what type of LCD it is and how it is connected to the driver chip.