My opinon on extra monitors

i agree with OP
my main is a 34" ultrawide 120hz..
but my 2 side monitors are
- left: landscape mode 21" widescreen at 60hz
- right: portait mode 21" widescreen at 60hz

i only use the left and right for game assist (like websites with walkthroughs for the game i play, using right portait monitor - better for websites)
or if i need to see a video of the walkthrough for puzzle games (using the left landscape monitor - better for videos).
but neither 'needs' to be more than 60gz