I'm not an antinatalist (though I lean more towards antinatalism than natalism) but I think that, in my case, it's better to never have been. After all, ignorance is bliss and there's nothing much more blissful than not having been born in the first.
I even think that the phrase can apply for the majority of humans living happy lives too. Yes, if they were never born, they would miss out on all of the happiness they experienced to become pro life but, simultaneously, they can't regret about any of it as non existent people cannot feel depressed over deprivation of pleasure. It's only in existence where people can feel depressed over deprivation of pleasure. And, from the point of birth, you don't yet know if that human would live a good life or if they'll suffer to the point where they'll consider ctb. Hence, in all cases, life is a gamble and the gamble isn't worth it as nothing would be lost had we never been born yet it would be possible to lose the lottery with your child and have them be depressed and/or incompatible with life if they were born