The hitex or hilatex program distributed with TEX Live 2023 will not produce PDF output, like other TEX engines, but it produces a HINT file. You can not display a HINT file with Acrobat Reader or any other PDF viewer. Instead you need a HINT file viewer. More about HINT viewers, examples, and downloads can be found on the HINT Viewer page. In contrast to a PDF viewer, a HINT viewer uses TEX's line breaking and page breaking algorithm to format the page you are currently viewing to fit the available size in the window or on your device. Look at this short demo video that was made for Jonathan Fines's TEX hour or at this video which was made for the TUG 2020 conference.
If you want to know more about it, there is an introductory paper in TUGBoat issue 39:3, 2018: HINT: Reflowing TEX Output.
Current version distributed with TEX Live 2023.
This version was the first public version distributed with TEX Live 2022.