Different bike are different, different riders are different. Different bikes get used by different riders to do different things. it is one hundred percent personal preference.

That said, a bike designed for one type of bars will likely feel Much different with another type, simply because of math. If you have a 100 mm stem m and 70 mm reach with drop bars, your hands are almost eight inches from the top of the head tube , and likely between 40-44 cm apart.

If you have a flat bar, your hands (and body weight as well as control input) are likely at least four inches back and possibly (depending on preference) several inches further apart. Different equations to resolve steering forces.

Sometimes bikes designed for flat bars will have longer top tubes. Slap drops on on of those and you might be riding in the Superman position.

BikesDirect offers a lot of solid bikes at good prices. Probably wort the wait. Go out and buy a few yard-sale bikes and play with them for a while to pass the time. Maybe even pick up a couple beat-down old-school rigid MTBs and combine parts to get them working, and abuse them for a while. Won't be new but will be strange, in a manner of speaking.