Have you worked with a curved monitor for any length of time? I ask because their appeal just does not last - at least not for many users. That's why they have not really grown in popularity.
The problem with curved monitors is there really is only one "sweet spot" to set your head to get the best viewing. Move a little bit to either side, and half the screen dims or becomes distorted as you move out of the ideal viewing angle. Move in too close or move away too far, and all but a thin center strip becomes dim or distorted. Unless you "triangulate" your head at just the right distance from screen center, that ideal viewing angle quickly moves out of that sweet spot for much of the screen. This has become a big problem for TVs where there is often more than one viewer. With computer monitors and only one person viewing, it may not be a problem - if you don't move around much.
I am not trying to talk you out of a curved monitor - just want you to understand the downside to them.
As for finding a monitor with the same brightness as your current Acer - that's going to be a problem. I've been a dual-monitor user for over 30 years. In fact, I don't see how anyone can live with just one monitor on their PC. One thing I have noticed over the years with probably dozens of different dual monitor setups is no two monitors are exactly the same when it comes to brightness and contrast. Even colors appear different. The best way to ensure both monitors have the same display characteristics is to buy two identical monitors - and even then there will be slight differences.