Options to deal with 43" monitor with MBP
I understand your goal is to be able to see as much as possible, even if that makes it smaller. In contrast, some people buy larger monitors so that everything appears larger, perhaps to compensate for poor eyesight.

Luckily macOS can accomodate for both preferences. In the System Preferences, under Displays, you can enable Scaled mode and choose More Space so that everything appears smaller, and you can see more things on screen at once.