Sometimes it’s hard to know where to start with getting devices working on a new platform, like I2C keypads, sensors and screens: here’s a writeup that provides some sample code to nicely interface plug-n-play SparkFun devices with a custom OS (NetBurner’s RTOS) with minimal reimplementation work. Would be similar for RT1062 devices like Teensy 4.1:

Use Qwiic I2C and SOMRT1061 for Rapid Prototyping
https://www.netburner.com/learn/use-qwiic-i2c-and-somrt1061-for-rapid-prototyping/

Use Qwiic I2C and SOMRT1061 for Rapid Prototyping
https://www.netburner.com/learn/use-qwiic-i2c-and-somrt1061-for-rapid-prototyping/