pdftk unicode works in preview but not adobe acrobat

I generate a PDF file and the unicode text appears in macos preview but not acrobat.

I have the following fdf file

%FDF-1.21 0 obj<</FDF<</Fields [<</T (name)/V <FEFF0793>>>]>>>>endobjtrailer<</Root 1 0 R>>%%EOF

The main thing is FEFF0793 which is utf16be encoded, and it should render the ޓ character (https://www.compart.com/en/unicode/U+0793)

pdftk form4.pdf fill_form fdf output 6.pdf

My form4.pdf

When I view it in MacOS preview, it doesn't appear until I click

but in acrobat it appears as a bullet point

Here is the fonts embedded. Whats the problem here? Why doesn't it appear in acrobat?

The font is from here: https://fonts.google.com/noto/specimen/Noto+Sans+Thaana

It's added to my MacOS fontbook, so not sure whats happening here. What if I had custom fonts that aren't part of my fontbook but I want to use their unicode values. What do I do here?