Let's focus on the MBR.
What is the exact model of the AC1200? Is it SingTel AC Plus or other router?
Next step is to carry out wireless speedtest in the MBR. You can use your laptop to measure wireless speed at different locations to identify the weak spots.
Optimizing the placement of the wireless router may help. You can try move your wireless router around in the MBR to see if that helps.
If in the end the result is not so good, then you can buy a better router.
Carry out the same exercise for the living room later for the AC Elite.
One possible solution is to upgrade AC Elite to a better one (eg: Asus RT-AX58U) and then move the AC Elite to the MBR to see if that performs better.
Thank you so much for the advices!


