Google lighthouse report has separate sections for SEO and accessibility. And I guess there could be other tools as well that provide feedback on accessibility metrics (like font background contrast). Does search engines like Google and Bing consider accessibility as a ranking factor?
The simple answer is "not really." The real answer is, "it depends."
Search engines don't care what your site looks like. If you use a light font on a light background that makes the text hard to read, they don't care. If the site is as ugly as a kid's first website from 1995, they don't care. A visually hideous site can rank highly for a search query. Nor do accessibility HTML standards like ARIA make a difference in SEO; those are for the user.
On the other hand, if your site's content is inaccessible to search bots, or accessible in a such a way that misrepresents or cloaks, then they will likely care very much.
Indirectly, however, accessibility can make a difference. Let's say your site content answers a search query very clearly, and begins to rank. However, it is too taxing for the user to read, and they bounce quickly. Those high bounce rate and low time on site may signal to search engines that this page should not rank highly, and it may drop off page 1 altogether.