Generally speaking, an unlikable character can drive readers away, but it’s not quite so black and white as that. The question you need to ask yourself is if your character is simply annoying, or does it possess some sort of evil genius that is important to the plot?
If your main character comes off as a whiny, spoiled brat that makes stupid decisions without any repercussions, then you may want to consider modifying their personality. However, if they are intelligent, menacing, and manipulative, it can create some great conflict for your other characters to work through.
It realistically makes no sense to have a story full of likable characters. This would result in boredom. You want your story to be memorable, and that means driving passions, even if it’s in a negative way.
Having said that, you still want to try and give the reader some closure on that unlikable character. Either find a way to make them likable or kill them off in an epic event.
How does your character make you feel? Use that as a guide, then rely on your beta readers to provide more insight. We tend to get attached to our characters and may not see them as less than perfectly written, so be open to the opinions of others.