For clarity and legibility as you described, scan the original document at a higher dpi as the source is most important. Also, in Lightroom, love the clarity slider. That said...
While not legal documents as you described, photos in general - original source document is most important. Unfortunately, during the past year I have been tasked to create a memorial slideshow video for two family members and another for an existing client's sister. NEVER AGAIN! Ignoring the emotional issue, with a "call for photos" the vast majority illustrates the "original source" issue. The majority of photos received were Facebook and other social media pulls. Even my mother, noone could find the original of the professional H&S shot she use for business and got the Facebook photo that was so small I would not print to an 11x14 without pixelation. Likewise all those photos that social media crunched their algorithms and reduced sized would pixelate within the video when shown on a 65" screen.
In my research to resolve the issue, I found two programs where could increase the file size and was able to minimize distortion. Topaz, which I didn't own, and On1 Photo Raw which I took the opportunity to upgrade to 2023. It did a great job on 95% of the photos, and the other 5% were hopeless. For my mother's photo which was placed on the counter during the Memorial, and a copy given to my brother and sisters, the maximum size the file would print was 4x6 and that was pushing it, as technically it was the size for a wallet photo. I took the print with studio lighting and took a photo of it with a 42mp camera, processed the RAW file, and had my local printer professionally print it. That definitely got around the small original file size.