I assumed you got it for the better image quality. That's my main reason
Agreed, was never too bad, but the point being made is dropping down to 144hz solved the issue. So dropping from 240hz to 120hz should make a difference.
Did you try dropping to 120hz to see if it made a difference?
As I recall DLDSR did make a decent difference. But yeah, not huge.
16:9 is life! Sell the 21:9 monitor already. Your friend is waiting to over pay when you are ready
Imagine faffing around using both monitors. That's a faff and a half