Ultrawide Primary Monitor + normal-size Extended Display results in font/cursor too small
I'm using a Samsung Odysee Neo 49" as my main monitor (which has been out for over one year), and a UPerfect 4K 15.4" as my extended display. They are both connected to the Mac Studio via USB-C to DisplayPort. This is perfect for Final Cut editing using the 15.4" as a preview viewer and the Ultrawide to see an expansive editing timeline.
But with the 15.4" correctly set to 4K (3840x2160) which I require for editing 4K content, macOS unfortunately misinterprets the monitors as being these relative sizes:
Obviously macOS has got this badly wrong, thinking the small monitor at the bottom is huge (because it incorrectly calculates it in comparison to the 5140x1440 resolution of the Ultrawide), and it results in windows, fonts, icons, and even the cursor, on the extended display looking unusably tiny:
Is there any way to fix this, whilst retaining 3840x2160 resolution for the small monitor?
Thanks in advance.