I think you r confused between the MIMO spec of LTE 4G and WIFI .
this 4x4 should be LTE 4G not for WIFI. U may get 1Gbps from your phone, if Yes/Maxis/Digi offer 1Gbps LTE internet speed.

AFAIK, no mobile phone is support 3x3 yet, coz more power consuming...
all we got now is either 2x2 or 1x1 MIMO for WIFI 802.11AC.. (nothing special, so nobody even mention about it in their advertisent).

btw, u still can get 3x3 or 4x4 for your laptop or pc. whislt most people choose to ignore them for saving money...

This post has been edited by hashtag2016: Oct 31 2018, 09:43 PM

so, the best u can get from 1x1 and 2x2 (Wifi 802.11ac) is 433Mbps and 866Mbps in theory.
(note: above calculation base on 256-QAM, 80Mhz)

edited@2018.11.01:
just found that Huawei Mate 20 Series which is using "Kirin 980 (7nm SoC) + Huawei Hi1103(wifi-chipset)" claimed to support 802.11ac wifi speed upto 1732 Mbps . It is using 2x2, 160Mhz bandwidth..
so, to reach the claimed peak speed, should ensure the wifi router support 160Mhz (VHT160) as well.

This post has been edited by hashtag2016: Nov 1 2018, 06:15 AM