Best Personal Laptop for Investment Banking?

I would still stick to the above:

1. Get a good dual monitor setup (might run you like $300ish).
2. Get a full keyboard on your laptop (fully built out arrow keys and ideally a number pad) because you'll utilize those while at work so it's good to practice with them (again, alternatively you can just plug in a normal $30 dell keyboard).
3. PC over Mac because you'll use a windows PC at work.
4. I would honestly advocate for building / buying a desktop for a fraction of the price. If you want a laptop as well for travel / personal reasons then again, go with a laptop with good USB / port selection and portable enough to travel with and buy the above peripherals.

Lenovo Thinkpads, Dell XPS line, Microsoft surface laptops (not the best port selection but they sell docks and I personally use one and like it) all come to mind. Honestly just do a youtube search of "best Laptop PC's 2019" and use that to initially narrow down the selection.