Not big on nail polish these days, but when the urge arises, it will be Kester Black. They have a not-too-humble array of shades, both classic and some, a little off kilter. My pick is Petal, an inoffensive neutral with a touch of mauve. It's a smooth formulation to apply. Easy to remove as well. Yes, there are likely many other nail polishes that would do a similar job, but this one ticks some other boxes that make it a better choice than much of its competition. Cruelty Free, B Corporation, Halal, Vegan, and Carbon Neutral. Does your nail varnish meet all the aforementioned criteria? Perhaps it should.
I have found the lid/applicator thingamajig can get a bit sticky but I am prone to screwing the lid on real tight so, in all likelihood, it's just a user issue. Nail polish noob alert.