Monitor Display Port 1.4 Vs 1.2. Is 1.4 That Much Better?

All

i know almost nothing about monitors

I am having a custom rig built and with Ryzen 9 3600, RTX 2060 super.

i just bought a monitor because it has G-sync it was ASUS VG278QR (£250). but i just learned its display port is 1.2 and not 1.4.

To be able to return the monitor and get a refund for something better i need to know within days if i should keep it or return it.

I need a monitor to be at least .
G-Sync compatible
27"+
144mhz refresh rate

I like the option of 4k but when will i use this? if ever. I do not know.

As i do more research on monitors i think i need one that has a 1.4 display port to make best use of gaming when using the RTX 2060 super?

I cannot work out if i will need a better monitor with display port 1.4 or keep what i have. this ASUS VG278QR has a refresh rate of 165. but will be using that with my new rig? will my rig be able to give me a better gaming experience but held back by the display port 1.2?

Is 1.4 that much better for gaming than 1.2? If so, by how much benefit will i get?

Should i send back the ASUS VG278QR and get a refund and opt for either of the below:

Pixio prime PX7
LG 27GL83A-B
LG 27GL850-B (might be to costly)
LG 27GL65F-B

Max i want to spend is £400

I have bought a Display port cable that handles 1.4 in preparation.

thank you all

 

not that sure myself, i'm invested in older hardware.
but here is some reading so you can decide.
https://www.cablematters.com/blog/DisplayPort/displayport-1-4-vs-1-2
and
https://www.howtogeek.com/661325/should-you-use-hdmi-displayport-usb-c-or-thunderbolt-for-a-4k-moni/