keeb.io have a number of different fully split but regular layout keyboards in various sizes. if you’re lucky enough to live nearby (North Carolina, USA), you could even visit their store to try things out. Otherwise, maybe you may be able to find someone with something like an Ultimate Hacking Keyboard (UHK) that you could try. something fully split is great because you can position the halves at whatever position and angle you like, even adjusting throughout the day. You know what they say, the best posture is the next posture.