I have been using Chat GPT, Microsoft Copilot, Google, scoured Reddit and other sites and couldn't find anyone that could get a PS5 Controller (Dualsense) working with Plex HTPC. I wanted to do this to setup a gaming PC as a console-like multimedia center using Playnite. Again, couldn't find the right answers anywhere. Using DS4Windows failed me, Steam Input didn't work, there were other controller mapping apps to use but ultimately, I was able to get it to work NATIVELY making a custom json. Just download this json file and place it in your Plex Inputmaps folder and BAM! it just works.

Link: PS5 Controller Json