skpang

Good to hear it works. There is a really good NMEA2000 library and Teensy driver by Timo. Worth a look: https://github.com/ttlappalainen/NMEA2000 Teensy 4 NMEA2000 with LCD example...

Check the baudrate on the Teensy. NMEA2000 normally runs at 250kbps. Your code is set at 1Mbps.

Check you have enabled the 120R terminator on both sides. Post a photo of your setup.

I have used this 1.54" 240x240 https://www.buydisplay.com/catalog/product/view/id/1815/s/1-54-inch-tft-lcd-display-ips-panel-screen-240x240-for-smart-watch/category/54/ It uses the ST7789 and there is a Teensy driver for it.

I use this connector from Mouser: https://eu.mouser.com/en/ProductDetail/Molex/15-91-0100?qs=UZEkBKezw1bF%2Fz6q%2FFjjLA%3D%3D&countryCode=GB&currencyCode=GBP

Have you measured the output voltage on the 5VDC wall adapter ? I've seen some are high as 5.2V Would really like to see a complete schematic of the board. Can't see the 3.3v regulator at the moment. If the 24v input is not on and you have the...

What 24VDC to 5VDC buck converter are you using ? Could be transient from the converter. Post a photo of your setup.