Hold your horses on replacing the whole bike! You only need to do that if you can’t get a good fit with a reasonably sized seat post and stem. Handlebar shape is a very personal choice. Bikes don’t come with pedals for a reason, but if it wasn’t a logistical nightmare, they would not come with handlebars, stems or saddles either. You are supposed to swap them.

Handlebar choice is almost as important as saddle for long term comfort. Hand numbness, wrist, arm, back, neck pain, even saddle comfort and endurance are all hugely impacted.

Best case would be to go to a shop with a fit cycle and try a bunch of different shaped and width bars and different reach measurements. Personally, I bought a bunch of cheap bars and stems until I found a setup that worked well, then upgraded. I got really good at wrapping bar tape in the process.