Can I use the Hyperpixel and the just boom zero dac hat at the same time. I know that hyperpixel is using all pins, but maybe it is possible through i2c.
Unfortunately not. i2c is just a simple data-bus for communicating between ICs- usually between the Pi and one or more external sensors. All of the DAC add-ons for the Pi use i2s, which has a subtly different name, but is totally different in implementation and purpose.
Unfortunately the i2s output pins are limited by the Pi hardware, and are taken up by the DPI output needed to drive Hyperpixel.
You’d have to use HDMI audio, analog audio or a USB DAC.