upgrade or downgrade?

[VanGoch]

So I have this 4k monitor Acer CB280HK that was great when I bought it (3-4 years ago). Now I have major problems with tearing and if I use vsync the input lag is terrible. 

I want to buy a new monitor with Gsync to eliminate tearing and input lag problems, but the problem is I can't go 4k because of all the new games.

So my plan is to buy a new Gsync monitor and if I can't go 4k should I at least get a 1440P and 120HZ?

My current one is 4k and I want to buy a 1440P 120HZ is this considered a downgrade or an upgrade? I mean I do get rid of the main problem I have with tearing, get some more HZ but loose some Pixels. What do you think? is it worth it?

 

Thanks in advance.

[APasz]

That's a sidegrade. So the question is, quality vs speed.