The problem here is that you can't really answer this question clearly.
Sure, a publisher can make a huge difference for your game, if the publisher in question is able to reliably get press coverage for their games, can port your game to other platform and also fund its development.
However, the pool of publishers who are actually able to do all these things is fairly small and getting signed by them is not easy. Larger indie publishers at this point are oftentimes looking for very specific games, that very often already either have additional financial backing, or have themselves generated a certain degree of public interest. That doesn't mean, that you shouldn't try pitching your game to them, but be aware that you might get rejected, even if your game is actually good.
The problem really starts with those indie publishers who are below that upper tier of companies, because the smaller the publisher in question, the higher the chance that you won't get anything in return for signing with them, aside from them taking 30-50% of your game's earnings.
How do you figure out which publisher might be worth your time? Look through their games catalogue and if they have released games on Steam, look at how many reviews each title has gotten. If the vast majority of their games has less than 100 reviews, I would say they are not worth your time, unless they give you money upfront (which they probably won't btw). This might change a tiny bit, if said publisher also offers to port your game to consoles, because there's still a certain degree of legitimacy that comes with that (at least that's what someone who knows more about this stuff told me), but still don't expect to get much money out of that arrangement.
And just more thing: If you want to have some kind of chance for people to actually find and buy your game on Steam, wait with releasing it, until it has at least 500-1000 Wishlists. That number still won't get you on the frontpage, but that way at least you can guarantee that you'll get a good number of sold copies, and hopefully enough reviews to get over that 10 positive review threshold.