I don't think first sentences are that important; other than being clear and understandable. In fact, I roll my eyes at pretentious first sentences, or those in which the author seems focused on having a killer first sentence.
Virtually all readers begin expecting to learn enough to get into the story. The amount of credit you get is highest on the first page, even the first few pages.
What you need to begin is an interesting scene.
Advice I've gotten from agents is to skip any exposition, or background, and never, ever start a story with a main hero idle and contemplating. Agents say never start with a prologue; they might be well done but they are a big red flag. They say start with a scene, with your hero, and get them interacting with others in the first three pages. No contemplation of the past, or how they got there, get to at least mild conflict fast.
That is what makes the scene interesting; they have some agenda. They wake up, there was a power failure at night, their alarm did not go off, they are late to work. Something is happening.
Don't look at old classics, ancient novelists had far more leeway. In modern novels, we get to know the characters through their troubles and actions; through scenes. Not by being told about their traits, or proclivities, or talents -- We see them in action.
That's your job, you've got about 750 words (3 pages) to get your main character talking to somebody else about something they want to achieve. Even if it is a throwaway, non-plot-central thing, like getting a plumber, or getting their lunch order right, whatever. A regular life problem is fine. They can't get their regular Apple Fritter for breakfast, somebody dropped the tray of apple fritters on the floor.
The first sentence doesn't have to grab anybody; you have all the credit in the world at that point, all you have to do is get into the scene and not bore the reader.
"Brenda always got off the bus one stop before her office, to buy her morning coffee and an apple fritter."
That is the moment before something unexpected happens. (No apple fritters today). And some little part of Brenda's character is revealed by how she reacts to the unexpected.
An interactive opening scene, and what exactly it reveals about your character, is important. Choose or devise that carefully. It can happen any day or night of the year. It shouldn't be too over the top, not typically life threatening. But preferably, you want to reveal something important about your character.
So IMO the first scene is very important and the first look at your character, but the first sentence does not have to be particularly outstanding.