Well, it depends what your goals are. However, you stated that the specialty you are trying to match into likes to have publications to enhance your competitiveness. If that it the case, I suppose you should try to pick something that will net you want to need. If you really think that a project is unlikely to lead you to an authorship, I would not suggest doing it at your stage (unless you really enjoyed the lab/mentor and didn't need the publication, but that's doesn't sound like the case). Likewise, I'll be honest, when I look at "publications" in ERAS, if they are case reports, I generally disregard them (though others might have different opinions, but there is no real research in case reports). In general, I would suggest you take the opportunity that has the best chance of your getting authorship or something, but also seems the most interesting/fun to you.
Also remember that not every research opportunity will lead to a manuscript and that is okay. There is a reason there is a "Research Experience" tab in ERAS, you so can explain what you did and what you learned, despite the lack of a publication. Personally, I think these count for a lot more than most people give credit for.