Does a lightbox feature for images improve accessibility?

Question

Consider a website that has accessibility (a11y) as a priority and implements it accordingly.

The site has quite a few images that contain detailed information (e.g., a screenshot of a historical document such as the United States Declaration of Independence), but due to the layout of the site, the images are not very large.
So, even if someone is not visually impaired, it may be difficult to identify the content/details in some of the images due to their size (not their quality).

To improve the a11y of these images, I first thought of implementing a lightbox feature (similar to what Wikipedia has implemented, as you can see from the link above).

However, I was concerned that having an <a> element around each image might be confusing to some users, especially those navigating with assistive technologies such as screen readers.

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To summarize my question, are lightbox links considered accessible and best practice on the web when implemented properly?

Is there any research or data on this topic? Is it sufficient to have appropriate alt text and rely on browser/system tools such as Zoom?