Space characters appear when trying to make accessible

[Patrick39031314z52u]

I wrote my thesis on Overleaf using LaTeX and then downloaded the final document as a PDF. In order to submit it, I need to add certain accessibility features to the document using Acrobat, including language, title, and alt text for the figures. The first two of these went fine, but when I clicked Prepare for accessibility > Add alternate text, Adobe told me that there were no figures in the document. Then, when I clicked Autotag Document and let it tag everything in the document including figures and paragraphs, it found the figures but added a bunch of unwanted dashes between words, which I take to be space characters that have for some reason been unhidden (see attachment).

How can I

1. Eliminate all of the space characters/dashes from the document, or

2. Add alt text to figures without running Autotag Document,

whichever is easier?