When short on space, can we add better link descriptions in the code and leave the link UI as-is?

Links need to be read by screen readers. Using the "read more" vs. "read more about accessibility" example, the first thing to consider when shortening the link text is that you need to ensure part of the visual label is still on the link. If the visual label is "Read more about accessibility," it would have to at least have "Read more" to avoid a label and name failure. If you were to shorten it, it would be accessible so long as there was enough surrounding content with the link to discern it will lead to accessibility information. If the link text is the only thing indicating where the link is pointing to, it would need to be a full description — and at that point, it might require some UI changes if the screen reader content is not in line.