Arabic text is not searchable in a PDF saved from Illustrator.
In Adobe Illustrator v. 29.2.1 (Middle Eastern version) on Mac OS 15.2, I created a document with A4 size page, typed any number of words, lines in Arabic Language.

I choose to save the file as PDF. Then in Acrobat, when I search for any Arabic word, I get the message "No matches were found".
The same text placed into Adobe InDesign or Microsoft Word, then Export the page as PDF. Those PDFs are fully searchable.

I believe that PDFs out of Adobe Illustrator are the only ones with this problem.

Note. This issue was reported by Samer_M who had posted his issue and attached PDF file on the Adobe Community Forums here…
https://community.adobe.com/t5/acrobat-reader-discussions/unable-to-search-for-arabic-words-in-a-pdf-document/m-p/15136014#M113476