DisplayPort solves the one problem HDMI was never designed to handle.
It might be why your PS5 doesn't perform like it should.
HDMI ARC or HDMI Audio Return Channel was introduced into the HDMI specification (in this case HDMI 1.4) in 2009 with a specific purpose: simplifying and improving the experience of getting audio from ...
It's not so much about using a wrong port, and more so about freeing up the more capable ones for needier devices.