I would recommend any bike with 8 or 9 speed in your budget that you tried and like to ride. Add the cost of a good U-lock and lights. As it eventually get stolen, save for a next bike.

8/9 speed parts are robust, abundant, and cheap, and maintenance is easy.

you might add to your list : choose a bank and insurance company that use your money for ecological/local/social projects

I know that I know nothing.

Is the motto since 2500 years, right? Right?