A 34” and 43” would require much higher resolutions than the Pro Display XDR to be high PPI for monitor usage aligning with what Apple accommodates (218PPI, 2 DPR)Apples displays are ridiculous. Small and expensive.
Ten years ago I had a 34" curved monitor. In 2019 I got a 43".
Even today Apple still doesn't sell a monitor the size I had 10 years ago.
If I was to get a new one today I'd probably aim around 50".
FWIW I work for a large public broadcaster. We produce everything from news to drama. We have thousands of Macs, yet we have zero Apple displays.
You’re sacrificing a lot of PPI with such sizes which is within your right.