I bought a stockpile of Microsoft Ergonomic Keyboard for Business (LXM-00001) when they were still available, after Microsoft announced discontinuing their peripherals. I hope they’ll last me for a long time. I don’t know if the curved geometry still counts as a traditional layout for you, though. Incase, who acquired Microsoft’s peripherals IP, has re-released them, but apparently can’t keep up with the orders: https://www.incase.com/products/ergonomic-keyboard
Check out the Feker Alice series of keyboards. The Alice 98 has a full set of function keys & numpad. High quality build, too, I've been very happy with it. The one & only thing I don't like about it is it's missing the Home and End keys, but I can live without them.
https://fekertech.com/products/feker-alice98-qmk-via
It has some good aspects, but it doesn’t go upwards in the middle (so that you can tilt your hands outwards), can’t be tilted backwards, and has no palm rest. Regarding the key layout, I’m addicted to the 3x2 navigation block unfortunately, as well as to the context menu key, and have no use for a Fn modifier key. I appreciate wide modifier keys; a single-width Ctrl key like on the right side or the Alt key on the left side won’t do. And I’d really prefer having Alt on both sides. Lastly, I don’t want the arrow keys to be lower than normal (if anything, I’d rather have them a little higher up).
No the single slab of keyboard is not quite what I want. Being able to fully separate my arms feels so much better than scrunching my shoulders all day.