The library is experimental as the functionality is not tested with hardware yet. The AD5231 is a single channel, 10 bit = 1024 step, SPI based potentiometer, the AD5235 is a dual channel version.
The MT6701 is an easy to program magnetic rotary position sensor with a high-resolution 12-bit analog, PWM, UVW, ABZ. With SPI and I2C output is 14 bit. They should provide magnetic button ...