Brand new? Or new to you? Most of my seating, including dining chairs, is vintage (I also have a few pieces that are authorized production of vintage designs). All are mid-century modern. My dining chairs are vintage molded fiberglass Eames chairs with their original Naugahyde covers. I've never found any dining chair made today that is even close to as comfortable. Of course, if mid-century modern isn't your thing, Eames is not for you. But you can still look for vintage chairs in a style that speaks to you. They are likely to be much better made than most chairs made today.

I know Arhaus has fans on this forum. I've seen a lot of complaints about Pottery Barn quality and (lack of) customer service. I can't speak from personal experience with either brand.

Perigold has a much wider selection of chairs. They can purchase just about anything.

Personally, I like some area on the chair that doesn't have upholstery so the chair can be moved without grasping fabric.

There are some nice classicly designed chairs available on Amazon if you search carefully.